the code review methodology

What is a code review?

A code review is a peer review of code that helps developers ensure or improve the code quality before they merge and ship it.

What are code reviews, and how do they work?

Code reviews , also known as peer reviews, act as quality assurance of the code base.

Code reviews are methodical assessments of code designed to identify bugs, increase code quality, and help developers learn the source code.

After a software developer has completed coding, a code review is an important step in the software development process to get a second opinion on the solution and implementation before it’s merged into an upstream branch like a feature branch or the main branch. The reviewer can also act as a second step in identifying bugs, logic problems, uncovered edge cases, or other issues.

This practice empowers code authors and reviewers alike to identify security flaws, adhere to quality standards, and share knowledge across programming languages and frameworks. Reviewers can be from any team or group as long as they’re a domain expert. If the lines of code cover more than one domain, two experts should review the code.

Why are code reviews important?

Developing a strong code review process sets a foundation for continuous improvement and prevents unstable code from shipping to customers. Code reviews should become part of a software development team’s workflow to improve code quality and ensure that every piece of code has been looked at by another team member.

The code review process is also an important part in spreading knowledge throughout an organization. For those reasons and more, 76% of developers who took the 2022 Global DevSecOps Survey said code reviews are “very valuable.”

What are the benefits of code reviews?

• Share knowledge: When software developers review code as soon as a team member makes changes, they can learn new techniques and solutions. Code reviews help junior developers learn from more senior team members, similar to how pair programming effectively helps developers share skills and ideas. By spreading knowledge across the organization, code reviews ensure that no person is a single point of failure. Everyone has the ability to review and offer feedback. Shared knowledge also helps team members take vacation, because everyone on the team has background knowledge on a topic.
• Discover bugs earlier: Rather than discovering bugs after a feature has been shipped and scrambling to release a patch, developers can immediately find and fix problems before customers ever see them. Moving the review process earlier in the software development lifecycle through unit tests helps developers work on fixes with fresh knowledge. When waiting until the end of the lifecycle to do a review, developers often struggle to remember code, solutions, and reasoning. Static analysis is a cheap, efficient way to meet business and customer value.
• Maintain compliance: Developers have various backgrounds and training that influence their coding styles. If teams want to have a standard coding style, code reviews help everyone adhere to the same standards. This is especially important for open source projects that have multiple individuals contributing code. Peer reviews bring in maintainers to assess the code before pushing changes.
• Enhance security: Code reviews create a high level of security, especially when security professionals engage in a targeted review. Application security is integral in software development, and code reviews help detect security issues and ensure compliance. Security team members can review code for vulnerabilities and alert developers to the threat. Code reviews are a great complement to automated scans and tests that detect security vulnerabilities.
• Increase collaboration: When team members work together to create a solution, they feel more ownership of their work and a stronger sense of belonging. Authors and reviewers can work together to find the most effective solutions to meet customer needs. It’s important to strengthen collaboration across the software development lifecycle to prevent information silos and maintain a seamless workflow between teams. To successfully conduct code reviews, it’s important that developers build a code review mindset that has a strong foundation in collaborative development.
• Improve code quality: Code reviews are an important way to ensure you ship high-quality code and quality software. A human who knows your code base can notice code quality issues that automated tests may miss. They can even help you reduce technical debt.

What are the disadvantages of code reviews?

• Longer time to ship: The review time could delay the release process, since reviewers have to collaborate with authors to discuss problems. Depending on a reviewer’s workload, they may not complete a review as fast as the author would like. This challenge can be overcome by using code review tools that include automated testing to find errors. Automated tooling is an effective way to free up developer time so that they can focus on the larger software engineering problems rather than highlight simple lint errors.
• Pull focus from other tasks: Developers often have a heavy workload, and a code review can pull their focus away from other high priority tasks that they’re responsible for delivering. Team members may be forced to decide between completing their task or halting their work in order to do a code review. In either case, work is delayed somewhere across the organization. To reduce this pain point, team members can have a reviewer roulette or a list of domain experts so that a single developer isn’t inundated with review requests.
• Large reviews mean longer review times: If developers have to conduct code reviews on a large change, they could spend a significant amount of time examining the code. Large code reviews are challenging to assess, and developers may naturally move through the process quickly in order to complete it in a timely manner, resulting in decreased feedback quality. Incremental code development prevents this challenge by enabling reviewers to look at a small piece of code several times rather than a large change at once.

Four approaches to code review

Some of these disadvantages can be minimized by selecting the most appropriate code review method for your team. Here are four common approaches to code review:

Pair programming

Pair programming involves two developers collaborating in real time — one writing code (the driver) and one reviewing code (the navigator). Pairing sessions are popular with development teams because teammates collaborate to identify the most effective solution to a challenge. Team members share knowledge and can quickly overcome difficulties by working through ideas together and drawing on their expertise.

The benefits of pair programming

• Transfers knowledge
• Prevents information silos
• Solves complex problems
• Increases morale
• Finds more bugs
• Can be conducted remotely

The drawbacks of pair programming

• Time-consuming
• Can be overused
• Difficult to measure

Over-the-shoulder reviews

In an over-the-shoulder-review, two developers — the author and reviewer — team up in person or remotely through a shared screen and the author explains the completed change proposal and offers reasoning for the chosen solutions. The reviewer asks questions and makes suggestions, similar to how team members collaborate during pairing sessions. The author can make small changes during the review and note larger fixes for a later time.

The benefits of over-the-shoulder reviews

• Easy implementation and completion
• Faster than pair programming

The drawbacks of over-the-shoulder reviews

• Reviewer is detached from code
• Review moves at the author’s pace
• Lack of objectivity
• No verification that changes were made

Tool-assisted reviews

Teams may decide to use tools to save time and ensure the highest quality code is shipped. Tool-assisted reviews can automatically gather changed files and display the differences, or make it easier to provide feedback and have conversations via comments, and incorporate things like static application security testing (SAST) to help identify and remediate vulnerabilities.

The best way to look at tool-assisted reviews is to consider them a complement to other types of reviews. Automated tooling is an effective way to enforce code standards, identify vulnerability, gather metrics, and gather files, but some teams may be tempted to completely rely on tooling and forgo team member involvement to conduct code reviews. Tools should be viewed as an extension of code reviews and a way to enhance the process.

The benefits of tool-assisted reviews

• Easier to gather metrics
• Automated tooling frees up developer focus

The drawbacks of tool-assisted reviews

• Developers must maintain tools
• Will still require teammate reviews

Email pass-around

Email pass-arounds are often used for minor difficulties and small pieces of code. They can be conducted via email or source code management systems. During an email pass-around, an author sends an email containing code changes to reviewers. Email pass-around is similar to over-the-shoulder reviews in that they can be easily implemented and don’t require a strong learning curve or a mentoring stage to teach the author how to make a change.

The benefits of email pass-arounds

• Facilitates remote, asynchronous reviews
• Automatic reviews via SCMs

The drawbacks of email pass-arounds

• Time consuming to gather files
• Difficult to follow conversations
• No definite review end date

Some best practices for code reviews

• Limit code review sessions to keep them productive. Figure out what works for your team — say, no more than one hour or 200 lines of code — and encourage them to stick to that limit.
• Include everyone — including new and senior members of the team — in the process. Code reviews are an excellent way to help newer members of the team get up to speed with the code base — both by reviewing code from and having their code reviewed by more senior developers on the team. Including everyone in your code review process will also make it easier to adjust when people go on vacation or are no longer on the team.
• Distribute code review requests amongst the team. It can be easy for a few developers to get the bulk of code review requests, and this won’t be good for them or the rest of the team — or the code base — long term. You can create a list of domain experts or a reviewer roulette to help avoid this.
• Ask questions and provide helpful context. When you’re reviewing someone’s code, do your best to help both of you learn during the process. Not sure why they did something a different way than you might have? Ask. Have a suggestion for how to improve their code? Don’t forget to tell them why you’re suggesting it in your comment. This will not only help you both learn, but it will likely save time.

By integrating effective code review practices into the fabric of software development, organizations can navigate the challenges of tight deadlines without compromising on the integrity of their products. The dialogue between the code author and the code reviewer lays the groundwork for a robust development process, ensuring that every piece of code not only meets but exceeds established standards.

Embracing code reviews is embracing a future where innovation, collaboration, and security drive the journey toward creating impactful software solutions.

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5 code review best practices

Improve code quality and help developers grow professionally with a well-thought-out code review process.

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In 1988, Hewlett Packard (HP) conducted an internal review of their software development processes and set a target to improve their code quality tenfold. To meet this ambitious goal, they tried a number of approaches. Eventually, they concluded that incorporating code reviews into the development cycle saved more money than resolving defects after they were found by customers.

A code review (also referred to as peer code review) is a process where one or two developers analyze a teammate’s code, identifying bugs, logic errors, and overlooked edge cases.

Granted, when HP made this realization, software development practices weren’t as well defined and mature as they are today. But organizations have long recognized that making code review a part of their software development lifecycle could result in positive outcomes.

More than three decades later, the software development industry is still exploring the benefits of code reviews. According to Smartbear’s survey from 2020, respondents voted code review as the number one way to enhance code quality.

Here are five code review best practices to maximize the value of a fresh perspective by identifying poor design patterns and bugs, ensuring that every new feature or product is created using high-quality code.

1. Create a code review checklist

A code review checklist is a predetermined set of questions and rules your team will follow during the code review process, giving you the benefit of a structured approach to necessary quality checks before you approve code into the codebase. Your checklist may include: 

• Readability : Are there any redundant comments in the code?
• Security : Does the code expose the system to a cyber attack?
• Test coverage : Is there a need to test more cases?
• Architecture : Does the code use encapsulation and modularization to achieve separation of concerns?
• Reusability : Does the code use reusable components, functions, and services?

2. Introduce code review metrics

5 tips for great code reviews

You can’t correct someone’s code quality without measuring it. Objective metrics help determine the efficiency of your reviews, analyze the impact of change on the process, and predict the number of hours required to complete a project.

Some commonly used review metrics include:

• Inspection rate : The speed at which your team reviews a specific amount of code, calculated by dividing lines of code (LoC) by number of inspection hours. If it takes a long time to review the code, there may be readability issues that need to be addressed.
• Defect rate : The frequency with which you identify a defect, calculated by dividing the defect count by hours spent on inspection. This metric helps determine the effectiveness of your testing procedures; for example, if your developers are slow to find defects, you may need better testing tools.
• Defect density : The number of defects you identify in a specific amount of code, calculated by dividing the defect count by thousands of lines of code (kLOC). Defect density helps identify which components are more prone to defects than others, allowing you to allocate more resources toward the vulnerable components. For example, if one of your web applications has significantly more defects than others in the same project, you may need to assign more experienced developers to work on it.

3. Ensure your feedback justifies your stance 

When reviewing code, don’t simply suggest what needs to be fixed or improved upon – explain why the developer should make that change.

During development, you’ll mostly deal with problems that can be solved with multiple solutions. The comments you include in the code are a product of your knowledge and experience; you might prefer tackling an issue in a specific way, which may be different from the code author’s approach. Therefore, you should articulate your coding choices to explain your reasoning.

For instance, suppose you review a piece of code where you don’t think multi-threading is required. Instead of simply advising the developer against using threads, explain that the concurrency model isn’t offering any performance advantage in their scenario and therefore they should make their code single-threaded.

There are two benefits to this approach. First, the code’s author will know why they should make a particular change, which will help them tackle similar problems in the future. Second, since you already justified your comments, they won’t need to follow up with you about the reasoning behind your comment, saving both of you time.

4. Don’t review more than 200-400 lines of code at a time

Reviewing more than 400 lines of code (LoC) can have an adverse impact on your ability to find bugs, and in fact, most are found in the first 200 lines. This limitation affected industry practices after Cisco identified it in a comprehensive study on code review.

The study found that, once developers reviewed more than 200 lines, their ability to identify defects waned (see the chart below).

5. Supplement your best practices with automation

If you use Bitbucket as your git solution, enhance your source code management (SCM) workflow with an app like Workzone , which can help you plan how and when to push changes and how to add reviewers and groups to new pull requests. You can also set predefined groups and reviewers to pull request source and branches, so newer pull requests include them by default. This way, organizations can implement their SCM process in a simple and user-friendly way.

Another Bitbucket app that can help you to automate your code reviews is Code Owners for Bitbucket . This tool lets you decide which users in Bitbucket should review pull requests using a concept known as code owners. Code owners are individuals who have knowledge and experience in a particular coding niche (e.g., developing applications in Spring Boot). Use code owners to ensure that the right developers have reviewed the code as merge checks.

To find more code review apps, browse the Atlassian Marketplace.

psa: code review is an opportunity for growth, not criticism

While building a code review culture, make sure your developers aren’t intimidated by the process. Avoid evaluating the performance of your developers by reviewing the defects identified during their code reviews. If this becomes a benchmark for promotion or compensation, your developers are likely to feel threatened by the process and hostile to it.

Instead, use code reviews as an opportunity to empower junior developers to learn from their senior counterparts. You’ll spot bugs earlier, when they’re cheaper to fix, improve coding standards compliance, and enhance the overall quality of your code. Approaching code reviews in this way creates an opportunity for your whole team to level up together, resulting in smoother, more efficient work on future projects.

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A 6-Step Code Review Process to Improve Code and Collaboration

What is code review .

A code review is a critical part of the software development process where the source code is systematically examined by one or more peers before it is merged into the main codebase. This practice aims to identify bugs, ensure coding standards are met, and improve the overall quality of the software. It’s a collaborative exercise that encourages sharing knowledge across the team, fosters learning, and enhances code maintainability.

Code review lies not just about identifying errors, but also about code optimization and adherence to coding conventions. This process enables developers to learn from each other and adopt best practices, leading to more efficient and reliable code. Moreover, it facilitates early detection of potential security vulnerabilities, significantly reducing the risk of security breaches post-deployment. 

Through constructive feedback, developers can refine their skills, contributing to the team’s overall expertise and the project’s success.

The Role of Code Review in CI/CD 

Code review is an important, if often overlooked, element in a Continuous Integration/Continuous Deployment (CI/CD) process. It acts as a quality gate that ensures only well-vetted and secure code is integrated into the main branch, supporting a rapid yet reliable release cycle. Code reviews ensure a level of quality that gives developers the confidence to automate many phases of the software delivery process.

Code review enhances collaboration and communication among team members. It allows for immediate feedback and iterations, making the development process more dynamic and responsive to change. Developers can address and rectify issues much faster, reducing the lead time for changes to be deployed. This continuous loop of feedback and improvement is crucial for maintaining high-quality standards in a fast-paced CI/CD environment.

Learn more in the detailed guide to CI/CD

Code Review Process Steps 

Here a structured process you can follow to implement code reviews in your organization:

1. Establishing Code Review Guidelines

Before diving into the review process, it’s crucial to establish clear code review guidelines. These guidelines serve as a roadmap for both reviewers and authors, ensuring that everyone is on the same page regarding what to look for and how to evaluate the code. 

Effective guidelines typically include criteria for code functionality, readability, and adherence to the project’s coding standards. They might also outline how to prioritize issues based on severity, from critical bugs to minor style violations. By setting these standards, teams can streamline the review process, making it more efficient and focused on areas that contribute most significantly to the project’s quality and maintainability.

In addition to technical aspects, guidelines should encourage a constructive and respectful feedback culture. This includes recommending language and tone that foster positive communication and growth. Guidelines might also suggest timeframes for review completion to ensure that the process does not become a bottleneck in the development workflow.

2. Reviewer Selection

Reviewers should have a good understanding of the project’s codebase and the technical expertise relevant to the code being reviewed. It’s often beneficial to include a mix of developers in the review process: those familiar with the specific subsystem or feature being changed and those with a broader perspective on the project. This diversity can lead to more comprehensive feedback, uncovering issues that might be missed by someone too close to the work.

Beyond technical skills, it’s important to consider the interpersonal dynamics of the team when selecting reviewers. Reviewers should be able to provide constructive feedback in a manner that is supportive and conducive to learning. In some cases, rotating the reviewer role among team members can help distribute knowledge and prevent any single individual from becoming a bottleneck.

3. Implementing Code Review Environment or Tools

The effectiveness of code reviews is significantly influenced by the choice of environment or tools used. 

Modern development workflows often leverage integrated development environments (IDEs) and code review platforms that facilitate the review process. These tools can highlight changes, facilitate inline comments, and support automated checks, making it easier for reviewers to provide precise feedback. Popular platforms like GitHub, GitLab, and Bitbucket offer built-in code review features that integrate seamlessly with version control systems.

Choosing the right tools can also enhance collaboration among team members who are not co-located. Features such as real-time notifications, threaded discussions, and the ability to suggest code changes directly can streamline the review process.

4. Code Inspection

The code inspection stage is where the core of the review takes place. Reviewers closely examine the code for issues related to functionality, security, performance, and adherence to coding standards. This involves not just looking for bugs but also assessing the code’s maintainability and scalability.

During this phase, reviewers might run the code, review unit tests, and check documentation to understand the changes fully. They look for code smells, potential optimization opportunities, and any deviations from the project’s coding conventions. 

It’s important for reviewers to approach this process with an open mind, considering the author’s intent and possible trade-offs they made. By focusing on significant issues that impact the project’s health and future development, reviewers can provide valuable insights that go beyond surface-level critiques.

5. Feedbacks and Comments

Providing feedback is a delicate art that requires balancing honesty with empathy. Effective feedback is specific, actionable, and focused on the code rather than the coder. Reviewers should clearly explain the reasons behind their comments, offering suggestions for improvement or asking clarifying questions.

Feedback should be organized and prioritized, distinguishing between mandatory changes and recommendations. Using a polite and respectful tone encourages a positive response and fosters a culture of continuous improvement. It’s also beneficial for reviewers to acknowledge what’s been done well, reinforcing good practices alongside identifying areas for improvement.

6. Final Approval and Merge

The final step in the code review process is the approval and merging of changes into the main codebase. This step usually requires at least one (or more, depending on the project’s rules) reviewer to formally approve the changes. 

Approval indicates that the code meets the project’s standards and is deemed ready for integration. However, if significant issues are identified during the review, the code may need to be revised and resubmitted for review, potentially undergoing multiple iterations.

Once approved, the code can be merged. This step should be accompanied by a clear commit message summarizing the changes and the review process. In some workflows, automated tests are run again post-merge to ensure that the new code does not break the build or introduce regressions.

Learn more in our detailed guide to code review checklist

Code reviews with Swimm

Code reviews are a hallmark of teams striving for high code quality and development best practices. However, They often create bottlenecks in the development process. The review process not only slows down the time it takes to ship code, it also often occupies some of the most talented and experienced developers on the team. Therefore, making code reviews more efficient can have a significant impact on a team’s velocity.

Swimm is an AI coding assistant that helps developers quickly understand large, complex codebases, while simultaneously capturing technical knowledge to fill in any documentation gaps. With Swimm, developers ask questions about their codebase and instantly get answers contextualized to their organizations codebase. 

Swimm can also be used to document Pull Requests, which helps streamline the review process and improve developer velocity. Once a PR is open, a document can be generated from it. Within seconds, AI will provide the developer with the context and reasoning behind the important changes in the PR, making the code review process faster and easier.

To try out Swimm, sign up for a 1:1 demo .

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6 Steps for a Solid Code Review Process

June 29, 2023 - 10 min read

Imagine you’re writing a book and you’ve just finished your first draft. This draft represents the code that’s just been written.

Your code is like your story. It has to be coherent, follow certain rules (e.g., syntax in code and grammar in writing), and ultimately achieve its purpose (e.g., to solve a problem or engage an audience).

The code review process is like the editing phase in writing a book. When you’re done writing your draft, you don’t immediately publish it. You give it to someone else to read — this person is like the code reviewer. 

Code review is crucial for software development teams to ensure quality output with minimal errors and risks. It’s a collaborative and iterative process, with the coder and team members (called peer reviewers) going back and forth, exchanging feedback, and making changes until all flagged issues are resolved and the code is up to standard.

This process requires careful oversight. From version control management to organizing feedback and following up with subsequent tasks and activities, software teams need proper IT project management tools to manage their work and create a structured, replicable process. 

This article discusses all you need to know about how to conduct a code review . We’ll talk about what it is, its top benefits, how to code review , and how a powerful project management platform like Wrike can improve your process for better results. 

What is a code review ?

A code review is a process in software development where one or more programmers examine another’s code to check for errors, bugs, or deviations from the project ’s standards. 

Through constructive feedback, the code review process seeks to improve the quality and maintainability of an organization’s codebase. The review cycle repeats until the new code meets set standards and is ready to be shipped or integrated into the main codebase.

Below are a few key aspects of a code review :

• Correctness: Does the new code do what it was designed to do? Does it reflect the requirements that were given to the developer? Does it handle potential edge cases correctly? Does it follow all regulatory and legal requirements?
• Readability: It’s important that the code is clear. Other developers (or even the code author in the future) should be able to understand the written code, even when the author is not available.
• Maintainability: Maintainability focuses on the code architecture and how easy it is to modify, integrate, or extend with the existing codebase in the future.
• Performance: While premature optimization can be a pitfall, a code review is an excellent opportunity to spot potential performance issues.
• Style and consistency: New code should follow a consistent pattern. Many development teams have style guides or use automated linters to enforce a style. Consistent codebases are easier to read and maintain.

It’s important to note that while code reviews can identify many types of problems, they are not a replacement for software testing . Rather, they are one part of a comprehensive software quality strategy.

Why is performing a code review important?

Now you understand what a code review is , let’s discuss why they are essential for every software feature or product launch in development.

Knowledge sharing

Giving feedback and sharing knowledge during code reviews creates an environment where team members learn from each other. When a developer reviews another’s code, they may learn something new about different approaches, algorithms, or techniques that were used. 

Reviewers learn from the author’s approach to solving problems, and the author gains insight from reviewers’ perspectives and experiences. Sharing knowledge about the company’s codebase also reduces the “ bus factor ” — the risk that only one person knows certain parts of the code.

Continuous improvement

Code reviews allow developers to give and receive feedback, enhancing team collaboration and continuous improvement. The iterative process of writing, reviewing, and revising code also encourages team members to improve their programming, communication, and teamwork skills. 

Promoting team ownership

What happens when you contribute to a project you weren’t initially a part of? You become invested in it. Code reviews promote a sense of collective ownership and responsibility. 

Everyone on the team gets a chance to provide input on different parts of the codebase, increasing their investment in its success and creating a sense of commitment and accountability, improving both the process and the final product.

Codebase consistency

Code reviews help ensure consistency in the coding style, which is vital for maintaining a clean, understandable, and transferable codebase. A consistent codebase reduces the build-up of technical debt and makes it easy for new developers joining a team to get up to speed and begin contributing. 

Building confidence

Conducting regular code reviews builds confidence in the software’s stability and functionality. Code reviews ensure multiple pairs of eyes examine the code, making it less likely that bugs or errors slip through to the final product. This enhances product confidence internally within the development team and externally with stakeholders and end users.

Reducing testing cycles

Although code reviews are not a substitute for testing, they can help reduce the number of testing cycles required by catching and fixing issues early in the development process. This way, developers save time and resources that would otherwise be spent on lengthy testing and debugging, resulting in a more efficient development process and a higher-quality final product.

Documentation

Through code reviews , developers can ensure that the code is well documented. Reviewers can check for the presence and quality of comments, making sure they accurately and concisely explain the code’s purpose. This makes the codebase easier to understand and reduces future technical debt.

What are the steps to a good code review process ?

Now let’s get into the practicals — how to code review . Below are steps to follow for a good code review process . 

1. Determine the purpose

Before beginning a code review , clarify why you’re reviewing the code. Are you looking to find bugs and errors? To check if the new code meets the project’s coding standards? To understand how well a new feature fits in with the codebase? Knowing the purpose will guide team members on what to look for during the review.

2. Use project management software

Using code review tools within project management software can make the process more efficient. This allows you to annotate code with comments, assign to team members, keep track of unresolved issues, and mark them as resolved when addressed. 

A project management platform like Wrike, for example, integrates with software development tools such as GitHub , making it easy to streamline your team’s workflow, automate incoming IT work requests , and create more time for developers to focus on the most important tasks. 

3. Review the code as a “code breaker”

The idea here is to approach the code review as if you’re trying to find ways it might break or fail. Look for edge cases that the code might not handle correctly. Consider how the code might perform under various conditions or with different input data. Also look for logical errors, unclear or duplicated code, shortcuts, and non-obvious code dependencies .

4. Determine if the code can be maintained

Good code is easy to maintain. Ensure your code review covers the following aspects: 

• Readability: Is the code easy to understand?
• Modularity: Is it well structured, with functionality neatly divided into functions or classes?
• Extensibility: Is it easy to add new features or change existing ones?

5. Vet for security

This step involves reviewing the code to identify any potential security vulnerabilities. This could include checking for issues like SQL injection vulnerabilities, improper error handling, hard-coded sensitive data, or inadequate encryption. Specialized tools like static analyzers can help but having at least one human reviewer is essential.

6. Communicate with the coder

Open and clear communication with your team is vital to a successful code review . Deliver feedback, both good and bad, constructively and respectfully. Remember that the goal is to improve the code, not to criticize the coder. 

Giving feedback on things the coder did well can help balance any negative criticism and make the code review process a positive one. Once the code is reviewed, communicate the findings to the programmer and give them a chance to respond and make necessary changes. You can leave comments in a GitHub pull request or use your chosen IT project management software.

Why should you always do a code review ?

Apart from the benefits above, it’s advisable to conduct code reviews to: 

Discover issues early

Reviewers often spot issues the code author misses. This may be as little as syntax errors or major, e.g., architectural problems and non-compliance with project specifications. Detecting issues early helps maintain the codebase’s stability and reduces the cost (in terms of time, money, and user trust) of fixing bugs late in the development process or after deployment. It can also prevent potential cascading problems that might have occurred if the issue were left unchecked. 

Increase security

Code reviews are immensely useful for checking new code for security flaws or potential vulnerabilities. This is especially important for applications that handle sensitive user data. Exposures may include poor error handling, inappropriate use of system resources, insecure communication, or potential areas for malicious injection attacks. A well-conducted code review by a developer who’s knowledgeable about security best practices helps ensure security is built into every feature and product from the start, reducing the risk of a breach later on.

Improve overall code quality

Code reviews not only help identify potential issues but also allow developers to suggest improvements and optimizations. The collective knowledge of the reviewing team leads to code that is more logical, robust, and suited to the organization’s needs. 

Improve your code review process with Wrike

There you have it — the foundational details about code reviewing. Before you get started on your own review, let’s recap:

Just like publishing a book without proofreading or editing will likely lead to a book full of unnecessary mistakes, shipping or merging code that hasn’t been reviewed can lead to avoidable flaws and shortcomings in your software project. 

This can be avoided by ensuring your code passes through multiple eyes and rounds of reviews to guarantee the best output possible. Conducting code reviews significantly elevates the quality of work delivered by a development team. 

Paired with a powerful enterprise project management platform like Wrike, IT project managers can perform code reviews , monitor software performance, identify gaps for improvement, and assign accountability for those tasks, all on one platform. 

Collaboration and project management go hand in hand as Wrike integrates with many IT apps and tools. Start with our PMO template to tailor your Wrike IT workspace to match how your team works.  

Whether you’re a scaling team now incorporating code reviews into your workflow or an enterprise looking for a better solution to manage IT projects, Wrike’s platform, features, and templates fit the bill. 

Kelechi Udoagwu

Kelechi is a freelance writer and founder of Week of Saturdays, a platform for digital freelancers and remote workers living in Africa.

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How To Create a Business Continuity Plan Template

Modern businesses face countless risks and challenges, and it is critical to have a business continuity plan (BCP) in place. A BCP helps an organization prepare for disasters, respond to disruptions, and recover in an efficient manner. In this article, we will walk you through a step-by-step guide on crafting the perfect business continuity plan template. Grab your notebook, and let’s dive in! Try Wrike for free Understanding the importance of a business continuity plan template A business continuity plan (BCP) is a preventive and proactive plan that helps an organization manage its operations during emergencies and disasters. It involves identifying and assessing potential threats and hazards that may disrupt a business’s operations. The purpose of a BCP is to minimize the impact of unexpected incidents. The goal is to ensure the company can maintain its essential operations with little interruption. Defining business continuity Business continuity refers to a business’s ability to continue its critical functions during a disruption, whether natural or human-made. This type of plan is a holistic approach that encompasses people, processes, and technology. Identifying potential risks and disruptions The initial stage in BCP development is assessing risks to identify potential threats that could affect the business’s operations. Organizations can categorize risks into internal or external factors, such as cyber threats, natural disasters, power outages, or supply chain disruptions. Once the organization has identified the risks, it needs to evaluate them to determine their potential impact. It’s crucial to assess both the likelihood of these risks happening and the potential consequences of not having a BCP. If a company heavily depends on its computers, a cyberattack or computer failure could be expensive and damage its reputation. A BCP can help mitigate these risks and ensure that the company can continue to operate with minimal disruption. The benefits of having a business continuity plan A BCP helps a company by reducing downtime, cutting financial losses, keeping employees safe, and protecting the brand’s reputation. It enables the organization to respond quickly and effectively to a disruption, resulting in minimal business interruption. Having a BCP in place can also increase customer trust and confidence in the companies ability to handle crises. Another advantage of having a BCP is that it helps spot areas for improvement in how the organization works. These changes allow for making processes more efficient, saving money, and becoming more resilient for the business as a whole. Try Wrike for free Lastly, BCPs hold organizations accountable, ensuring compliance with regulatory requirements. Failure to comply with certain regulations can result in fines and reputation damage, along with endangering employees and customers. Key components of a business continuity plan template A BCP template has the following key parts: analyzing business impact, recovery plans, incident responses, crisis communication, and training. A BCP template is an essential tool for ensuring business continuity. In addition to the key parts mentioned, it should also include clear roles and responsibilities for employees during a crisis. These roles can help streamline decision making and ensure a swift response to any disruptions. Furthermore, the template should incorporate regular testing and revision of the plan to adapt to evolving threats and changing business needs. Good business continuity planning is an ongoing process that protects your organization and makes it stronger when facing challenges.  Let’s take a closer look at each of these components: Business impact analysis A business impact analysis (BIA) consists of two main parts. The first part involves identifying important functions within the organization. The second part involves determining how a disruption could impact the business’s finances, reputation, and compliance. Keep doing this analysis regularly to make sure it stays current and helpful for the business’s present operations. Recovery strategies Recovery strategies are what a company does to fix important things when something bad happens, using info from the BIA. These strategies include recovering data and systems, relocating staff, or seeking assistance from another company until things are back to normal. Remember to document the recovery strategies in detail and have them regularly reviewed and updated. Regularly test them to ensure they function well and you can use them quickly if there’s an issue. Communication and crisis management A communication and crisis management plan tells you how to talk to employees, suppliers, regulators, and customers when something goes wrong. The plan should ensure everyone understands the company’s response to the problem and its impact on the business. Training and awareness Make sure employees understand the BCP through education and regular training so they know what to do during disruptions. This preparation helps the organization respond effectively and minimize disruptions to its operations. Overall, your program should include training on the BIA, recovery strategies, incident response plan, and communication and crisis management plan.  Try Wrike for free Step-by-step guide to creating a business continuity plan template Business continuity planning is a critical process for any organization. Here is your step-by-step approach to creating a BCP template. Step 1: Assemble a business continuity team Assemble a business continuity team consisting of employees from various departments and functions, such as IT, operations, finance, and human resources. These staff members, who know the organization’s important tasks, will create and put the BCP template into action. Also, it is important that the team members have the necessary resources and support to carry out their responsibilities effectively. This may involve giving the team training, making sure they have the right tools and technology. Step 2: Conduct a risk assessment Next, conduct a comprehensive risk assessment to identify internal and external risks that may impact the organization’s operations. The assessment should consider a range of scenarios, including natural disasters, cyberattacks, and other potential disruptions. It should also take into account the potential impact of these risks on the organization’s critical functions.  Step 3: Identify critical business functions After assessing risks, determine which essential tasks must continue during a disruption. Critical functions are the top tasks the organization needs to prioritize, such as assisting customers, handling orders, and managing finances. Remember to involve key stakeholders in the identification of critical functions.  Step 4: Develop recovery strategies Next, develop recovery strategies that outline the procedures for restoring each function in the event of a critical disruption. Make sure you test and validate your strategies for effectiveness so you can implement them quickly and efficiently. This testing may involve conducting simulations or other exercises to identify any gaps or weaknesses in your recovery strategies. Step 5: Create an incident response plan Craft a plan that provides details on how the organization will respond to an incident. Ensure the procedures detail how to reach the crisis management team, evaluate the situation, and talk to stakeholders, employees, and customers. Make sure the plan explains how to use recovery strategies from Step 4 quickly and effectively when there’s a problem. Step 6: Establish a communication plan Develop a communication plan that outlines how to approach all stakeholders, employees, and customers regarding the disruption and the organization’s response. This plan needs a crisis management team, and their job is to organize how the organization deals with the problem. Establish this team in advance, and have their contact information readily available. Step 7: Train and educate employees Train and educate employees on the BCP and their responsibilities so that they know what to do during a disruption. Do practice runs often to make the plan work better. Everyone, including those not in the business continuity team, should take part. Step 8: Regularly review and update the plan Every year, go and update the BCP template to ensure accuracy. This will make sure it still works and fits any changes in the company’s operations, risks, and threats. It is also important to review the BCP following any significant changes to the organization’s operations or infrastructure. This may include changes to key personnel, IT systems, or the business’s physical location. Business continuity plan example In this business continuity plan example, we’ll explore the key components of a robust strategy to ensure an organization can weather unexpected disruptions. Let’s consider a manufacturing company. Its BCP might include strategies for relocating production to alternate facilities in case of a natural disaster or supply chain interruption. It may also detail communication protocols to keep employees, customers, and stakeholders informed during such events. Additionally, the plan could address data backup and recovery procedures to ensure critical information remains accessible. With a good business continuity plan, organizations can avoid long disruptions. They can keep a good reputation and hold on to trust from customers and partners, even in tough times. How Wrike can help with a business continuity plan template Wrike helps organizations create and maintain a good business continuity plan by being a flexible project management and collaboration platform. By leveraging Wrike, businesses can streamline their continuity planning efforts in several ways. Wrike helps team members communicate and work together easily, with real-time updates and task assignments — especially important during crises. Secondly, the platform supports comprehensive document management, making it easy to store and access critical documents, such as emergency response protocols and contact lists. Moreover, Wrike’s customizable workflow automation guarantees that it meets crucial tasks and deadlines without fail. This enhances the speed and efficiency of responding to disruptions, ensuring that the business can recover quickly and minimize downtime.  In summary, Wrike provides a robust framework for designing, implementing, and maintaining a business continuity plan, helping organizations safeguard their operations and respond effectively to unforeseen challenges. Conclusion A BCP is essential for any organization that wants to ensure business continuity during a disruption. You can create a BCP template by following the steps in this article. This template will assist your organization in managing risks and recovering from disruptions. Remember to review and update your plan regularly and educate your employees to ensure its effectiveness. Ensure your organization’s resilience by crafting an effective business continuity plan template with Wrike. Start your free trial today and safeguard your business from unforeseen risks and disruptions. Note: This article was created with the assistance of an AI engine. It has been reviewed and revised by our team of experts to ensure accuracy and quality.

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Code Review — The Ultimate Guide

by Assaf Elovic

Code Review — The Ultimate Guide

The ultimate guide for building your team’s code review process.

After conducting hundreds of code reviews, leading R&D teams and pushing several unintentional bugs myself, I’ve decided to share my conclusions for building the ultimate code review process for your team.

This article assumes you know what a code review is. So if you don’t, click here for a great intro.

Let’s quickly state some straightforward reasons as to why you should do code reviews:

• Can help reduce bugs in code.
• Validate that all coding requirements have been filled.
• An effective way to learn from peers and get familiar with the code base.
• Helps maintain code styling across the team.
• Team cohesion — encourage developers to talk to each other on best practices and coding standards.
• Improves overall code quality due to peer pressure.

However, code reviews can be one of the most difficult and time-consuming parts of the software development process.

We’ve all been there. You might have waited days until your code was reviewed. Once it was reviewed you started a ping pong with the reviewer of resubmitting your pull request. All the sudden you’re spending weeks going back and forth. You are context switching between new features and old commits that still need polishing.

If the code review process is not planned right, it could have more cost than value.

This is why it’s extremely important to structure and build a well-defined process for code reviews within your engineering team.

In general, you’ll need to have in place well-defined guidelines for both the reviewer and reviewee, prior to creating a pull request and while it’s being reviewed. More specifically:

Define perquisites for creating pull requests.

I’ve found that the following greatly reduces friction:

• Make sure code compiles successfully.
• Read and annotate your code.
• Build and run tests that validate the scope of your code.
• All code in codebase should be tested.
• Link relevant tickets/items in your task management tool (JIRA for example) to your pull request.
• Do not assign a reviewer until you’ve finalized the above.

Define reviewee responsibilities

While the reviewer is last in the chain of merging your PR, the better it’s handed over by the reviewee, the fewer risks you’ll run into in the long term. Here are some guidelines that can greatly help:

• Communicate with your reviewer — Give your reviewers background about your task. Since most of us pull request authors have likely been reviewers already, simply put yourself in the shoes of the reviewer and ask, “How could this be easier for me?”
• Make smaller pull requests — Making smaller pull requests is the best way to speed up your review time. Keep your pull requests small so that you can iterate more quickly and accurately. In general, smaller code changes are also easier to test and verify as stable. When a pull request is small, it’s easier for the reviewers to understand the context and reason with the logic.
• Avoid changes during the code review — Major changes in the middle of code review basically resets the entire review process. If you need to make major changes after submitting a review, you may want to ship your existing review and follow-up with additional changes. If you need to make major changes after starting the code review process, make sure to communicate this to the reviewer as early in the process as possible.
• Respond to all actionable code review feedback — Even if you don’t implement their feedback, respond to it and explain your reasoning. If there’s something you don’t understand, ask questions inside or outside the code review.
• Code reviews are discussions, not dictation — You can think of most code review feedback as a suggestion more than an order. It’s fine to disagree with a reviewer’s feedback but you need to explain why and give them an opportunity to respond.

Define reviewer responsibilities

Since the reviewer is last in the chain before merging the code, a great part of the responsibility is on him for reducing errors. The reviewer should:

• Be aware to the task description and requirements.
• Make sure to completely understand the code.
• Evaluate all the architecture tradeoffs.
• Divide your comments into 3 categories: Critical, Optional and Positive. The first are comments that the developer must accept to change, and the latter being comments that let the developer know your appreciation for nice pieces of code.

Also, avoid many comments and use Github review instead (see example below).

When you have several comments, you should use the review option in Github, instead of comment each of them separately, and notify the developer (PR owner) when you’re done.

Finally, I’ve found that asking the following questions is a great tool for an overall better and easier reviewing process:

• Am I having difficulty in understanding this code?
• Is there any complexity in the code which could be reduced by refactoring?
• Is the code well organized in a package structure which makes sense?
• Are the class names intuitive and is it obvious what they do?
• Are there any classes which are notably large?
• Are there any particularly long methods?
• Do all the method names seem clear and intuitive?
• Is the code well documented?
• Is the code well tested?
• Are there ways in which this code could be made more efficient?
• Does the code meet our teams styling standards?

There are various effective and different code review practices that vary based on team’s needs. So assume this is my personal opinion and that there are other ways that might work for your team. In the end, building such a sensitive process should be subjective to your companies goals, team’s culture and overall R&D structure.

If you have any questions or feedback for improving these guidelines, please feel free to add a comment below!

If this article was helpful, share it .

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code review

Code review is a systematic software quality assurance technique for developers in which the code is reviewed to find and fix errors, improve code quality, and enforce coding standards.

Table of Contents

• What is a peer code review?
• Automated code review
• Is a code review important?

How to do a code review

What are code review tools.

• Automated code review tools
• Automated code review tool benefits
• Sonar and code reviews

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Code review is a software quality assurance process where one or more persons or tools systematically examine and evaluate the source code of a program. One or more of the individuals reviewing the code need to read the code and identify any issues within the code. 

The goal of code reviews is to identify bugs, improve code quality, and follow best practices and standards for coding.

Code reviews are typically performed before integrating the code into the main branch of the codebase and can also be done periodically for existing code to maintain its quality over time. 

The process of code review helps catch errors early in the software development lifecycle (SDLC), fosters collaboration among team members, and ultimately leads to a more robust and reliable software product.

There are code review tools that can assist with automating the review process. These review tools can check for coding errors and provide recommendations for improving the code. 

If the code review is performed manually, at least one of the individuals should not be the author of the code. 

What is a peer code review? 

Peer code review is a software development process in which one or more developers examine code generated by a peer before merging it into the main repository. This method is intended to improve software quality, detect defects and vulnerabilities early, share expertise among team members, and ensure coding standards are followed.

Peer code review can be done in a variety of ways, but the primary method is for the reviewer to read the code and look for errors. The code reviewer may also question the author about the code in order to better grasp its intent. 

What is an automated code review?

An automated code review is a process in which static code analysis tools are used to automatically review and analyze the source code for potential issues and coding standard violations.  Automated code review accelerates the identification and resolution of code issues and improves code quality (reliability, security, maintainability).

Different from peer review where a human is manually looking through code line by line, automated code reviews utilize tools to detect a wide range of errors from bugs and vulnerabilities to styling issues. As compared to manual peer review, automated code review tools can quickly and efficiently scan codebases to identify defects, security vulnerabilities, coding style violations, and other potential problems.

Some common issues normally highlighted with automated code review tools include:

• Syntax errors
• Logic errors
• Security vulnerabilities
• Code style violations
• Compliance with coding standards

These kinds of code inspections are essential in current DevOps and Continuous Integration/Continuous Deployment (CI/CD) processes.

Why is a code review important?

Code review is an important method for increasing software quality. It can aid in the detection of defects and errors, the improvement of code readability, security, and maintainability, and the exchange of knowledge early in the development process. By implementing code reviews earlier in the development life cycle, you can save time and money later on in the process. 

By utilizing code reviews earlier on also, it can be made easier for future developers to work on and understand the code that is evaluated. This helps promote knowledge and collaboration among team members along with fostering shared code ownership. 

What is a secure code review?

Secure code review is a subset of code review that focuses on detecting potential security flaws and weaknesses in a codebase. Its goal is to ensure that the application’s codebase is resistant to potential security threats and follows secure coding practices. It's a proactive strategy that aids in the detection and correction of security flaws before the application goes live. This can prevent attackers from exploiting weaknesses in the code.  

Secure code review can be performed manually, by a security professional or developer reviewing the code line by line, or automatically, with secure code review tools that scan the code and flag errors. The code reviewer looks for common security issues in the code such as injection flaws, Cross-Site Scripting (XSS) vulnerabilities, and authentication and authorization issues. 

Secure code review is an important aspect of the software development lifecycle (SDLC) since it can assist in identifying and correcting security flaws before they are exploited by attackers. The reviewer looks over code to identify known vulnerabilities like those mentioned in the OWASP Top 10 along with concerns unique to the application or dev environment. 

Typically, the process includes both manual and automated reviews. Manual reviews can evaluate the logic and design of the code, identifying issues that other tools may overlook. Automated tools rapidly scan vast codebases for common vulnerabilities and coding errors, increasing the efficiency of the review process.

Code reviews are an essential element of the software development process that can considerably improve the final product's quality. 

Here's a step-by-step guide to performing a code review:

Prepare for the review

Set some time aside to become accustomed to the code before beginning the review. This includes reading the code, knowing its purpose, what the code is supposed to do, and comprehending the team's coding standards.

Understanding the goal and context of the code modification is critical.

Start the review

You can begin the review once you are familiar with the code. The review should be a two-way dialogue between you and the code's author. You should ask the author questions regarding the code, and they should explain their decisions. 

Review the design

Determine whether the suggested solution is consistent with the application's existing architecture and design patterns. If the implementation diverges significantly, it is worthwhile to demonstrate why and how the alternate solution improves the project.

Check correctness

Ensure that the code functions as expected and achieves its intended goal. This could include manually executing and testing the code, examining automated test results, or simply confirming that appropriate testing was performed.

Look for any problems as you go through the code. This involves searching for logic mistakes, security flaws, performance difficulties, and readability issues.

Review code style and standards

The code should follow the coding style and standards of the team. Code style consistency makes the code easier to read and understand. This includes correct indentation, naming conventions, and code organization.

Check for code smells

Code smells can indicate more serious issues in the code. Large classes or methods, redundant code, magic numbers, or excessive complexity are examples. If you notice a code smell, it's worth talking about and possibly refactoring .

Examine Readability 

The code should be easy to read and understand. Good code usually is self-explanatory. 

Review tests

Ideally, code changes should be accompanied by tests. Ensure that there is appropriate test code coverage and that the tests are testing the functionality correctly.

Evaluate security and performance

Analyze the code for possible security vulnerabilities and performance issues. If the code adds new features, make sure they don't have an adverse effect on the application's performance or security.

Provide feedback

When you notice problems, give clear, constructive comments. Explain what's wrong, why it's a problem, and, if possible, provide a solution. Be courteous and professional in your remarks.

Communicate

If you have any concerns or questions, don't be afraid to ask them. It is preferable to clarify uncertainty rather than make assumptions. Code review is more than just looking for bugs; it's also an opportunity for discussion and learning.

Summarize your review

When you're through, write a summary of your findings. Depending on the conclusion of your review, you can approve the modifications, suggest revisions, or just include comments.

Resolve issues

After reviewing your suggestions, the developer should be able to remedy the issues. This could include changing the code or justifying their decisions.

The purpose of a code review is not only to find problems but to promote sharing knowledge, cooperation and continuous learning with the team. When executed properly, code review may greatly enhance the quality of your code. 

Code review tools are software applications that help in the code review process. These tools work to improve the organization, efficiency, and effectiveness of code reviews by include capabilities such as side-by-side comparisons, automated analysis, commenting systems and integration with version control systems.

Here are a few factors to think about when selecting a code review tool:

• The project's size and complexity. Larger and more sophisticated tasks may necessitate the use of more powerful tools.
• The available budget. Some code review tools are open source and free, while others are not.
• The functions provided by the tool. Some tools provide more features than others.
• The tool's ease of use. Some tools are more user-friendly than others.

Certain code review tools with version control systems include:

They use a Pull Request or Merge Request functionality to help with code reviews.

What are automated code review tools?

Automated code review tools are software applications that analyze code automatically to find bugs, security flaws, and coding standards violations. These tools employ static code analysis, which examines the code without running it. The major purpose of these tools is to improve the efficiency of the code review process by spotting common errors, allowing human reviewers to focus on more difficult areas of the code.

What are the benefits of automated code review tools?

The following are some benefits of utilizing automated code review tools:

Improved code quality

Automated code review tools can greatly enhance code quality by identifying common programming errors, code smells, and potential security vulnerabilities.

Increased efficiency

Automated code review tools assist in making the code review process more efficient. This is due to the fact that they can scan code far faster than a human reviewer across multiple codebases. 

Improved accuracy

Automated code review tools can improve code review accuracy. This is due to their ability to detect potential flaws and weaknesses that a human reviewer may overlook.

Consistency 

These tools enforce the same rules to all code in the same way, ensuring that coding standards and guidelines are followed consistently throughout the project.

You can scale dramatically because these tools can handle code reviews for massive codebases where manual reviews cannot. They excel at such workloads and is one of the primary advantages of using automated tools. 

Reduce risks

Automated code review tools can reduce the risk of errors and vulnerabilities in source code. This is because they may detect possible issues before they are put into production.

Sonar and Code Reviews

Code reviews play a vital role in modern software development. Sonar streamlines the review process, enhances code quality, and fosters best practices in coding; complementing traditional manual code reviews by quickly detecting issues that might be time-consuming or challenging for humans to spot, ensuring a more efficient and robust code review process.

SonarQube is an open-source based Clean Code tool for continuous code quality inspection. It conducts automated code reviews using static analysis to find defects, code smells, and security issues. It works with continuous integration/continuous deployment (CI/CD) pipelines and supports over 30 programming languages. It has an extensible architecture to allow developers to write custom rules and plugins to adapt the analysis to their specific needs.

SonarCloud is a cloud-based version of SonarQube, providing the same powerful code analysis and quality monitoring capabilities but without the need for on-premises hosting. It offers automatic analysis and pull request decoration, enabling developers to get code quality feedback directly within their version control platform during code review. Both SonarQube and SonarCloud play a crucial role in improving code quality, identifying security vulnerabilities, and enforcing coding standards in software projects.

.css-moha17{padding-bottom:32px;margin-bottom:32px;} SonarCloud is a key part of our workflow since our first few months as a startup. It provides valuable insight into our review process, allowing code reviewers to shift the focus from conventions and cleanness to functionality, design, and risk management. .css-182swpd{display:block;font-weight:700;font-size:14px;line-height:21px;margin-top:24px;}@media (min-width: 1120px){.css-182swpd{font-size:18px;line-height:28px;}} .css-1a7nw27{height:32px;width:32px;border-radius:9999px;margin-right:16px;vertical-align:middle;} const t="undefined"!=typeof HTMLImageElement&&"loading"in HTMLImageElement.prototype;if(t){const t=document.querySelectorAll("img[data-main-image]");for(let e of t){e.dataset.src&&(e.setAttribute("src",e.dataset.src),e.removeAttribute("data-src")),e.dataset.srcset&&(e.setAttribute("srcset",e.dataset.srcset),e.removeAttribute("data-srcset"));const t=e.parentNode.querySelectorAll("source[data-srcset]");for(let e of t)e.setAttribute("srcset",e.dataset.srcset),e.removeAttribute("data-srcset");e.complete&&(e.style.opacity=1,e.parentNode.parentNode.querySelector("[data-placeholder-image]").style.opacity=0)}} German Bobr , .css-275ehg{font-weight:400;font-size:14px;line-height:21px;}@media (min-width: 1120px){.css-275ehg{font-size:18px;line-height:28px;}} C-suite (CIO/CTO/CISO) @ Inviu

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A complete guide to code reviews

Code reviews are a widely accepted best practice for software development teams. In this post, we'll cover why the most successful teams use code reviews, how to adopt them in your development process, and what the best practices are.

The goals of code reviews are:

• Sharing knowledge: The depth of know-how shared depends on the thoroughness of the review, but some amount of information will always be transferred. The knowledge can be general tips about the framework or programming language or invaluable domain-specific information bits.
• Spreading ownership: Code reviews have a positive impact on mutual code ownership. It's easy to end up in a situation where one developer always deals with a certain part of the codebase because they're most familiar with it. It might be a short-term win but is often a long-term loss. When ownership is shared, teams become more motivated and autonomous.
• Unifying development practices: Every developer has their own tendencies and ways to implement software. Code reviews help to narrow the gap between individual development styles and make the codebase more unified. Unification happens through high-level discussions about architecture and software design and via micro-level continuous integration checks, such as coding style enforcement.
• Quality control: Studies have shown that code reviews can help with catching defects, but even more importantly, they surface software design issues while they are still relatively easy to change.

Adopting code reviews

It's crucial to set the review process right. At worst, code reviews might feel like a hindrance. At best, code reviews help to sustain a good, stable team performance for many years.

If your organization is new to code reviews, introducing them will be a big change in the development process. Whenever implementing changes to ways of working, it's a good idea to ensure that everyone agrees on the process and has had the chance to contribute to the decision. This will cause less friction.

You, as a team or an organization, should agree on the philosophy and motivation behind code reviews before implementing them. You can write down an internal "what's a good code review" document together or refer to existing guides. It's a practical way to make sure everyone is aware of the whys.

Social relationships can't be ignored when talking about peers giving feedback about each other’s work. There are no silver bullets. It's hard work that requires each individual's contribution. To have the best chance of success, make sure to thoroughly discuss and educate your team about communication practices.

Best practices for code reviews

Blog posts about review practices often mention smaller details about branch names, commit message lengths, etc. While those tips are valuable too, this post focuses on more general recommendations.

There are multiple perspectives to a code review process: the author's, the reviewer's, and the team's point of view. Each party has an equally important role in the process. Some best practices apply only to the author or the reviewer, but many of them are important for everyone in the team.

Let's go through what those practices are. We'll focus on GitHub and pull request (PR) oriented review processes, but many of the tips apply in general as well.

1. Decide on a process

Responsibility will bounce between the author and the reviewer(s). The more explicit the review process, the less likely the ball is dropped by any party.

For example, our internal PR guidelines look something like this:

• DRAFT You can open a PR in a draft state to show progress or request early feedback.
• The review is done by another team member.
• Usually, there's no need to request a review; Swarmia automatically notifies the team. A manual review request can be useful if you, for example, want to request a design review from a certain designer.
• It's polite to have the PR ready so that you're not about to rebase everything 5 times while the reviewer tries to keep up.
• Preferably, create new commits after the review.
• You can directly commit suggestions from the GitHub UI.
• APPROVED The author is responsible for merging their own PR.

Yours might look different, but as long as the team agrees on the process, all is good.

2. Focus on the right things

To maintain code review standards across developers, it's a good idea to have guidelines for what to focus on in code reviews. Here's what we recommend focusing on:

• Functionality : Does the code behave as the PR author likely intended? Does the code behave as users would expect?
• Software design : Is the code well-designed and fitted to the surrounding architecture?
• Complexity : Would another developer be able to easily understand and use the code?
• Tests : Does the PR have correct and well-designed automated tests?
• Naming : Are names for variables, functions, etc. descriptive?
• Comments : Are the comments clear and useful?
• Documentation : Did the author also update relevant documentation?

Developers shouldn't spend their time reviewing things that can be automatically checked. More on that in "Use continuous integration effectively" and "Delegate nit-picking to a computer" .

3. Discuss the high-level approach early

Before jumping into coding a complex feature, it's beneficial to discuss the high-level approach first. Usually, this is done when planning the feature.

It's not nice for anyone if a PR ends up in a complete rewrite because the approach wasn't discussed beforehand. Rewrites of pull requests do happen every once in a while, but it's a sign that you might want to talk more before the implementation.

Sometimes a proof-of-concept implementation is needed to ignite the discussion. An effective way to get started is to open a draft PR of the approach and make the architecture decision based on the gained information.

4. Optimize for the team

This idea is explained well in Google's Engineering Practices document:

We optimize for the speed at which a team of developers can produce a product together, as opposed to optimizing for the speed at which an individual developer can write code.

Speedy reviews increase team performance in multiple ways: iteration becomes faster, developers don't need to do time-costly context switches as often, etc. Make sure the team understands the implications of fast reviews and agrees on a suitable maximum time for responding to a PR. The key is to minimize the response lag between the author and the reviewer, even if the whole review process takes long. For example, it might be invaluable for the author to know that their PR will be reviewed, for example, tomorrow morning.

That said, developers shouldn't interrupt their focus to do reviews. Instead, they should prioritize them whenever there's a fitting gap—for example after lunch.

Review speed is definitely not solely the reviewer's responsibility—the author has an important role too. The easier it is to pick a pull request and review it, the faster the work flows. Our help article "Review Code Faster" covers how to leverage Swarmia to speed up reviews.

5. Default to action

Sometimes reviews can stall for various reasons. During those times, you should have a bias for action. One can approve a PR even if there's some input left for the author to consider.

If a tech decision lingers and work becomes blocked, deciding something relatively quickly is better than slowly concluding to an "ideal" decision. Reserve enough time for technical decisions, but move on before you reach analysis paralysis. Developers should be inclined to merge code instead of primarily focusing on poking holes in the implementation.

6. Keep pull requests small

Smaller batches are easier to design, test, review, and merge. There are studies [1] [2] about the optimal amount of changed lines, but it's not an exact science. Google's recommendations put it well:

There are no hard and fast rules about how large is “too large.” 100 lines is usually a reasonable size for a CL, and 1000 lines is usually too large, but it’s up to the judgment of your reviewer. The number of files that a change is spread across also affects its “size.” A 200-line change in one file might be okay, but spread across 50 files it would usually be too large.

It's almost always possible to split a large change into smaller chunks—for example, with a separate refactoring PR that sets the stage for a cleaner implementation. Practicing slicing also helps to detect minimal shippable increments of your product.

Feature gates or feature flags might be necessary to gain the ability to ship half-ready product features along with the existing ones. Learn more why small pull requests are better .

7. Foster a positive feedback culture

Effective communication, in general, is really hard. Giving feedback about a colleague's work is one of the most challenging forms of communication. Acknowledge this in code reviews.

Here's a list of suggestions to improve discussions in code reviews:

• Give feedback about the code, not about the author.
• Pick your battles.
• Accept that there are multiple correct solutions to a problem.
• You're in the same boat.
• PR authors are humans with feelings (except dependabot 🤖).
• Provide reasons, not feelings, to support your position.
• Use the "Yes, and..." technique to keep an innovative atmosphere. It can be an ungracious pattern to dismiss fresh and fragile ideas in a draft PR stage.
• Keep the feedback balanced with positive comments. It's always delightful to receive praise from the reviewer.

If the pull request discussion becomes heated, schedule a call to discuss the topic. It usually helps to relieve the tension.

8. Use continuous integration effectively

GitHub Actions and status checks are widely used for building a robust CI pipeline. However, no matter the tools, it's crucial to invest in setting up a CI solution to automate as many quality checks as possible.

Automated checks allow reviewers to focus on more important topics such as software design, architecture, and readability. Checks can include tests, test coverage, code style enforcements, commit message conventions, static analysis, and much more.

A variety of metrics produced by continuous integration can help the reviewer to quantify the quality of a PR. Test coverage and code complexity metrics might reveal interesting insights that otherwise would be hard to estimate. These metrics don't necessarily need to be hard pass or fail checks but rather additional data for the review process.

Instead of slowing down the review process to catch more bugs, try to improve the automated checks to enable fast movement.

9. Delegate nit-picking to a computer

Whenever a reviewer spends their time nit-picking on small details, consider if it could be an automated check. Automatic check will always be enforced, while the human process relies on the reviewers' memories and moods to reject an anti-pattern.

For example, our ESLint rules enforce a consistent usage of certain terminology across the product. This is far more effective than documentation that would list the correct spelling of each word.

Code formatting is an example of a controversial topic in which almost all solutions are correct. Spending time debating stylistic choices rarely provides much value to the product, as long as a set of rules are adopted. Consistent unpleasing styles (to some individuals) are better than a mixture of multiple styles.

Your team can also adopt pre-existing practices, for example, a TypeScript project could adopt Prettier defaults instead of re-inventing their own.

10. Communicate explicitly

When reviewing a piece of code, be explicit about the action you request from the author. Let's say a reviewer has commented, "This could be done in Postgres in favor of application code" on a line of code. Are they requesting a change, suggesting to refactor it later, or just making the author aware of other solutions? It's often hard to judge. GitHub provides tools to be more explicit: for example, "Request changes" in a review.

Tip for the PR author: dismissing a review resets the pull request state to indicate that the reviewer can review again. It's up to you, the PR author, to decide if it feels important enough to use the feature, but especially in remote teams, it might help to make the process even more explicit.

11. Use explicit review requests

Review requests in GitHub are a convenient way to let others know that your code is ready for review. While a review can be requested manually, we recommend setting up a CODEOWNERS file to automate requesting a review. The method is robust and doesn't rely on individual authors remembering to request reviews.

Reviews can also be requested from a team, via CODEOWNERS or manually, which distributes the responsibility among team members. Make sure reviews are done evenly by all developers instead of siloing reviews to a single person.

12. Review your own code

Before submitting a PR for a review, go through the changes yourself. This helps to catch accidentally included changes, typos, and other simple mistakes that potentially waste the reviewer's time.

13. Document as much as possible in code

When receiving a comment or suggestion, aim for documenting the discussion in code. If the reviewer is not sure what the validateUsers function does, elaborate on the functionality ideally by renaming the function or writing a comment in the code. This way, the next developer that reads the code will understand the functionality without reading the PR discussions.

In some cases, the author can copy-paste their PR discussion response as is to comment in the code.

14. Write clear PR descriptions

The reviewer forms a mental picture of a pull request from multiple information sources: feature planning, description in the issue tracker, PR description, commit messages, chat history, etc. The more coherent the picture is, the faster and higher quality the review is. Decide on the team’s preferred channels to communicate certain information.

At Swarmia, we use PR descriptions to fill the technical gaps that the Jira issue description didn't cover. The additional details often include information such as what setup is needed to test the PR, surprising implementation details, and anything that makes the reviewer's job smoother. There are also other ways to add information: code comments, commit messages, commenting on individual lines in a PR as the author, etc.

Demo in any visual form is a nice touch. The format can be a screenshot, a screen capture, terminal output pasted in a code block, or anything that captures the change well. GitHub supports both videos and GIFs in the PR descriptions.

In addition to a static demo video, it's a great practice to build preview versions of your application per PR branch. The ability to interactively test the application preview without setting up anything in a local development environment saves time and increases the likelihood of someone manually testing a pull request.

Remember that the fidelity of descriptions required depends on the context.

You, as a team, need to figure out the perfect balance between explaining nothing or everything.

GitHub also supports issue and pull request templates if you want to standardize parts of the descriptions.

15. Use the shared repository model

For most private repositories, we recommend starting with the Shared repository model :

In the shared repository model, collaborators are granted push access to a single shared repository and topic branches are created when changes need to be made.

This model makes many aspects of the review process in GitHub simpler than the forking model that is popular among open-source projects.

16. Keep discussions public

It's convenient to have a quick chat about a pull request in the office, but be mindful of colleagues working remotely. It's polite to add a summary of face-to-face discussion as a PR comment.

Pull request discussions are searchable and easily accessible by all developers. They act as a history log of discussion which might be incredibly valuable when debugging a production incident later on.

Wrapping up

That concludes our complete guide for code reviews—and you know what that means in a company blog: a quick sales pitch!

If you're interested in improving your code reviews beyond what GitHub can offer, take a look at our code insights . Swarmia’s pull request view enables convenient access to your open pull requests, Slack notifications help your teams review code faster, and working agreements help you follow the practices that you've agreed on together with your team.

Additional reading

• Google's Engineering Practices
• How to Make Good Code Reviews Better by Gergely Orosz
• How to Make Your Code Reviewer Fall in Love with You by Michael Lynch
• Code Review Guidelines for Humans by Philipp Hauer
• Reducing Pull Request Cycle Time with Swarmia

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How to Make Good Code Reviews Better

I have been doing day-to-day code reviews for over a decade now. The benefits of code reviews are plenty: someone spot checks your work for errors, they get to learn from your solution, and the collaboration helps to improve the organization’s overall approach to tooling and automation. If you’re not currently doing code reviews in your organization, start now. It’ll make everyone a better engineer. Plenty of people and organizations have shared their code review best practices and what the definition of good code reviews mean to them. Guides from Google , the SmartBear team , and engineer Philipp Hauer are all excellent reads. Below is my personal take on what good code reviews look like and how to make them even better at the team and organizational level. This is in the context of the tech environment I have been working at - currently at Uber, and before that at Skype/Microsoft and Skyscanner. Good code reviews are the bar that all of us should strive for. They cover common and easy to follow best practices that any team can get started with, while ensuring high-quality and helpful reviews for the long term. Better code reviews are where engineers keep improving how they do code reviews. These code reviews look at the code change in the context of the codebase, of who is requesting it and in what situation. These reviews adjust their approach based on the context and situation. The goal not only being a high-quality review, but also to help the developers and teams requesting the review to be more productive.

Areas Covered by the Code Review

Good code reviews look at the change itself and how it fits into the codebase. They will look through the clarity of the title and description and "why" of the change . They cover the correctness of the code, test coverage, functionality changes, and confirm that they follow the coding guides and best practices. They will point out obvious improvements, such as hard to understand code, unclear names, commented out code, untested code, or unhandled edge cases. They will also note when too many changes are crammed into one review, and suggest keeping code changes single-purposed or breaking the change into more focused parts. Better code reviews look at the change in the context of the larger system, as well as check that changes are easy to maintain. They might ask questions about the necessity of the change or how it impacts other parts of the system. They look at abstractions introduced and how these fit into the existing software architecture. They note maintainability observations, such as complex logic that could be simplified, improving test structure, removing duplications, and other possible improvements. Engineer Joel Kemp describes great code reviews as a contextual pass following an initial, light pass .

Tone of the Review

The tone of code reviews can greatly influence morale within teams. Reviews with a harsh tone contribute to a feeling of a hostile environment with their microaggressions. Opinionated language can turn people defensive, sparking heated discussions. At the same time, a professional and positive tone can contribute to a more inclusive environment. People in these environments are open to constructive feedback and code reviews can instead trigger healthy and lively discussions. Good code reviews ask open-ended questions instead of making strong or opinionated statements. They offer alternatives and possible workarounds that might work better for the situation without insisting those solutions are the best or only way to proceed. These reviews assume the reviewer might be missing something and ask for clarification instead of correction. Better code reviews are also empathetic. They know that the person writing the code spent a lot of time and effort on this change. These code reviews are kind and unassuming. They applaud nice solutions and are all-round positive.

Approving vs Requesting Changes

Once a reviewer completes their review, they can either mark it approved, block the review with change requests, or not set a specific status, leaving it in a “not yet approved” state. How reviewers use the approve and request changes statuses is telling of the code reviews. Good code reviews don't approve changes while there are open-ended questions. However, they make it clear which questions or comments are non-blocking or unimportant, marking them distinctively. They are explicit when approving a change - e.g. adding a thumbs up comment like “looks good!”. Some places use acronyms like LGTM —these also work, but be aware that newcomers could misinterpret these insider acronyms for something else. Good code reviews are equally explicit when they are requesting a follow-up, using the code review tool or team convention to communicate this. Better code reviews are firm on the principle but flexible on the practice: sometimes, certain comments are addressed by the author with a separate, follow-up code change. For changes that are more urgent than others, reviewers try to make themselves available for quicker reviews.

From Code Reviews to Talking to Each Other

Code reviews are usually done asynchronously and in writing through a code review tool. This is usually out of convenience, to enable remote code reviews, and to allow multiple people to review the same code change. But when is it time to stop using the tool—however good it might be—and start talking face to face about the code? Good code reviews leave as many comments and questions as are needed. If the revision does not address all of them, they will note those as well. When the conversation gets into a long back-and-forth, reviewers will try to switch to talking to the author in-person instead of burning more time using the code review tool. Better code reviews will proactively reach out to the person making the change after they do a first pass on the code and have lots of comments and questions. These people have learned that they save a lot of time, misunderstandings, and hard feelings this way. The fact that there are many comments on the code indicates that there is likely some misunderstanding on either side. These kinds of misunderstandings are easier identified and resolved by talking things through.

Nitpicks are are unimportant comments, where the code could be merged without even addressing these. These could be things like variable declarations being in alphabetical order, unit tests following a certain structure, or brackets being on the same line. Good code reviews make it clear when changes are unimportant nitpicks. They usually mark comments like these distinctively, adding the “nit:” prefix to them. Too many of these can become frustrating and take the attention away from the more important parts of the review, so reviewers aim to not go overboard with these. Better code reviews realize that too many nitpicks are a sign of lack of tooling or a lack of standards. Reviewers who come across these frequently will look at solving this problem outside the code review process. For example, many of the common nitpick comments can be solved via automated linting. Those that cannot can usually be resolved by the team agreeing to certain standards and following them—perhaps even automating them, eventually.

Code Reviews for New Joiners

Starting at a new company is overwhelming for most people. The codebase is new, the style of programming is different than before, and people review your code very differently. So should code reviews be gentler for new starters, to get them used to the new environment, or should they keep the bar just as high, as it is for everyone else? Good code reviews use the same quality bar and approach for everyone, regardless of their job title, level or when they joined the company. Following the above, code reviews have a kind tone, request changes where needed, and will reach out to talk to reviewers when they have many comments. Better code reviews pay additional attention to making the first few reviews for new joiners a great experience. Reviewers are empathetic to the fact that the recent joiner might not be aware of all the coding guidelines and might be unfamiliar with parts of the code. These reviews put additional effort into explaining alternative approaches and pointing to guides. They are also very positive in tone, celebrating the first few changes to the codebase that the author is suggesting.

Cross-Office, Cross-Time Zone Reviews

Code reviews get more difficult when reviewers are not in the same location. They are especially challenging when reviewers are sitting in very different time zones. I have had my fair share of these reviews over the years, modifying code owned by teams in the US and Asia, while being based in Europe. Good code reviews account for the time zone difference when they can. Reviewers aim to review the code in the overlapping working hours between offices. For reviews with many comments, reviewers will offer to chat directly or do a video call to talk through changes. Better code reviews notice when code reviews repeatedly run into timezone issues and look for a systemic solution, outside the code review framework. Let's say a team from Europe is frequently changing a service that triggers code reviews from the US-based owner of this service. The system-level question is why these changes are happening so frequently. Are the changes done in the right codebase or should another system be changed? Will the frequency of changes be the same or go down over time? Assuming the changes are done in the right codebase and the frequency will not go down, can the cross-office dependency be broken in some way? Solutions to these kinds of problems are often not simple and could involve refactoring, creating of new services/interfaces or tooling improvements. But solving dependencies like this will make the life of both teams easier and their progress more efficient for the long term, meaning the return on investment is often quite impressive.

Organizational Support

The way companies and their engineering organizations approach code reviews is a big element of how efficient they can be. Organizations that view them as unimportant and trivial end up investing little in making reviews easier. In cultures like this, it might be tempting to just do away with code reviews entirely. Engineers advocating for doing better code reviews might feel isolated, without support from above and eventually give up. The result is an organization where problems continue to repeat and compound upon themselves. Organizations with good code reviews ensure that all engineers take part in the code review process—even those that might be working on solo projects. They encourage raising the quality bar, and teams facilitate healthy discussions on code review approaches both at the team and org level. These companies often have code review guides for larger codebases that engineers initiated and wrote. Organizations like this recognise that code reviews take up a good chunk of engineers' time. Many of these companies will add code reviews as expectations to the developer job competencies, expecting senior engineers to spend a larger chunk of their time reviewing the code of others. Organizations with better code reviews have hard rules around no code making it to production without a code review—just as business logic changes don't make it to production without automated tests. These organizations have learned that the cost of cutting corners is not worth it; instead, they have processes for expedited reviews for urgent cases. These organizations invest in developer productivity, including working continually to develop more efficient code reviews and tooling improvements. Helpful engineering executives don't need convincing on the benefits of code reviews and other engineering best practices. Instead, they support initiatives on better tooling or more efficient code review processes that come from teams. When people come across reviews that feel hostile, they feel they can speak up and have support all-round to resolve the issue. Senior engineers and managers consider code reviews that are not up to the bar just as much of an issue as sloppy code or poor behavior. Both engineers and engineering managers feel empowered to improve how code reviews are done.

Start With Good, Make it Better

Good code reviews already have lots of good effort going into them. They do a thorough review of the change itself, avoid being opinionated with the tone of comments, and make nitpicks clear. They maintain a consistent bar, regardless of who is requesting the review and try to make cross-time zone reviews less painful by paying additional attention to these. Organizations that have good reviews ensure that every developer regularly receives and does code reviews. This is already a high bar—but if you get here, don’t stop. Code reviews are one of the best ways to improve your skills, mentor others, and learn how to be a more efficient communicator. Get to better code reviews by continuously improving on the details, but also start looking at changes at a high level as well. Be empathetic in the tone of comments and think of ways outside the code review process to eliminate frequent nitpicks. Make code reviews especially welcoming for new starters and look for systemic solutions for painful cross-time zone reviews. Organizations that are forward-looking encourage investing in tooling and process improvements to make code reviews better, reaping more of the benefits. ------- Gergely is currently an engineering lead in Amsterdam. This blog post originally appeared on Gergely’s blog, The Pragmatic Engineer . If you’d like to read more from Gergely, you can subscribe to his monthly newsletter for his articles on engineering, tech leadership and distributed systems. If you would like to contribute articles to the Stack Overflow blog, send an email to [email protected].

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Mastering Code Reviews: Best Practices for Effective Development Workflows

Code Reviews, the Biggest SDLC Bottleneck?

Code review, while a crucial component of the Software Development Life Cycle (SDLC), can often be perceived as a bottleneck for several reasons:

• Balanced quality and speed: Code reviews prioritize the code quality. This often requires time and attention to details, slowing down the rapid pace at which developers might be churning out code. The inherent tension between wanting to maintain high-quality standards and wanting to release features quickly can cause delays.
• Limited expertise: Not all team members may be equipped to review certain pieces of code, especially if it's in a domain or technology they're unfamiliar with. Waiting for the right expert to be available can introduce delays.
• PR size : In a busy development environment, the sheer volume of code changes can be overwhelming. Large pull requests (PRs) or merge requests are harder to review than smaller ones. It takes time to understand, evaluate, and provide meaningful feedback on large chunks of code.

• Asynchronous communication: Developers may be spread across different time zones, especially in today's remote-first work environments. Waiting for feedback from a colleague in a different time zone can introduce delays.
• Lack of clear guidelines/scoping : Without a clear set of guidelines or a checklist for code reviews, the process can become subjective. Different reviewers might focus on different aspects, leading to inconsistent feedback and prolonged back-and-forth discussions.
• Cognitive load: Reviewing code requires a high degree of concentration. A reviewer needs to understand the context, the problem the code is solving, and any potential implications of the code changes. This cognitive load can be taxing and time-consuming.
• Avoiding difficult conversations: Sometimes, reviewers might find issues with the code but might hesitate to give negative feedback, fearing conflicts or the possibility of coming across as overly critical. This can delay the review process as they might take more time to phrase their feedback or avoid it altogether.
• Dependency chains: Code awaiting review might be dependent on other code that's also under review. This creates a chain of dependencies where one delayed review can hold up several others.
• Tool limitations: While there are many tools available for code reviews, they might not always be optimized for the specific needs of a team. The wrong tool can introduce inefficiencies in the review process.
• Continuous integration (CI): Sometimes, the code review process might be waiting on automated tests to pass in a CI environment. If there's a queue or if the CI process is slow, it can add to the delay.

While code reviews can introduce delays, it's essential to remember that their primary purpose is to ensure code quality, maintainability, and knowledge transfer among team members. Addressing the above challenges through better processes, tools, training, and communication can help to optimize the code review process within the SDLC.

In this article, we’ll cover the basics of code reviews and why they are important, the code review process and best practices, the common pitfalls and how to avoid them, and we’ll provide you with an overview of the tools and platforms to help streamline code reviews. 

The Basics of Code Review

Brief History of Code Review

The history of code review traces its roots back to the early days of software engineering and has evolved over time to address the changing needs and technologies in the software development field.

Early Peer Reviews

Before the term "code review" became widespread, the concept of reviewing work done by peers was already practiced in other fields. In software engineering, this approach became more formalized in the 1970s and 1980s as the industry began to recognize the importance of quality assurance.

Structured Walkthroughs

One of the earliest formalized methods of code review was the " structured walkthrough ". This process involved the author of the code presenting their work to a group of colleagues. The group would then critique the code and suggest improvements.

Fagan Inspections

In 1976, Michael Fagan of IBM formalized a code inspection method known as the " Fagan Inspection ". This method included roles such as the author, inspector, reader, and moderator, and it had a defined process comprising stages like planning, overview, preparation, inspection, rework, and follow-up.

From Formal to Lightweight Reviews

While methods like Fagan Inspections were detailed and rigorous, they were also time-consuming. As software development methodologies evolved, especially with the rise of Agile and Continuous Integration/Continuous Deployment (CI/CD), there was a move toward more lightweight, iterative code review processes. Tools like pull requests in Git-based platforms (like GitHub, GitLab, and Bitbucket) facilitated this shift.

Modern Tools and Practices

The rise of distributed version control systems, especially Git, has transformed the code review landscape . Platforms such as GitHub, Bitbucket, and GitLab introduced features that allowed developers to review and comment on code changes directly within the platform. These tools made it easier for teams, including distributed teams, to collaborate, discuss, and iterate on code changes.

Automation and Static Analysis

As technology advanced, tools were developed to automate parts of the code review process . Static code analysis tools could automatically detect certain code patterns, bugs, or potential vulnerabilities, allowing human reviewers to focus on the logic and design aspects of the code.

In conclusion, the practice of code review has evolved over the decades from formal, structured processes to more agile and tool-integrated practices. The emphasis throughout, however, has remained on improving code quality, fostering collaboration, and ensuring that software is maintainable and free of critical errors.

The Primary Goals of Code Review

The primary goal of code review is to ensure and improve the quality of software. This overarching objective can be broken down into several facets:

• Identifying and correcting bugs : One of the main reasons for code reviews is to catch errors or bugs that might have been overlooked by the original developer. By having another set of eyes (or multiple sets) review the code, the likelihood of spotting and addressing these issues increases.
• Maintaining code consistency: Code reviews help ensure that the codebase remains consistent in terms of style, structure, and design. This consistency makes the code easier to read, understand, and maintain in the long run.
• Ensuring code security: Security vulnerabilities can be introduced inadvertently. Through code reviews, developers can spot and rectify potential security issues before they become larger problems.
• Knowledge sharing and transfer : Code reviews facilitate the sharing of knowledge among team members. Developers become familiar with different parts of the codebase, learn new techniques, and understand the rationale behind certain decisions.
• Promoting best practices: Code reviews help reinforce best practices in coding, design patterns, and software architecture. They act as a platform for team members to share and discuss better ways to achieve a certain task or function.
• Building team cohesion: The collaborative nature of code reviews fosters improved communication and understanding among team members. They become more aligned in their approach to coding and problem-solving.
• Validating software design: Beyond just the code's syntax and logic, reviews can also validate the overall software design. Reviewers can provide feedback on the architecture, data flows, and other high-level design aspects.
• Documentation and comments: Ensuring that code is well-documented and that comments are meaningful is another goal of code reviews. Proper documentation aids future maintenance and provides clarity for other developers who might work on the code.

While ensuring and improving code quality stands out as the primary goal, the benefits of code reviews span various aspects of software development, from technical to interpersonal.

Why Code Reviews Are Essential

Code Review for Quality Assurance

• Error detection: A key aspect of quality assurance is the early detection and correction of errors. When multiple developers review code, the probability of identifying and rectifying mistakes, bugs, or inefficiencies increases.
• Standard enforcement: Code reviews help enforce coding standards and best practices. Consistent adherence to standards is vital to ensure that the software behaves reliably and predictably.
• Security: During the review process, vulnerabilities or potential security loopholes can be identified and addressed. Given the critical importance of software security, this facet of code reviews is vital for quality assurance.

Code Review for Knowledge Transfer

• Shared understanding: When developers review each other's code, they gain insights into different parts of the codebase and the rationale behind specific implementations. This shared understanding aids in overall system comprehension.
• Mentorship: More experienced developers can provide guidance and suggestions to less experienced team members during reviews, helping them learn and improve their skills.
• Continuous learning: Even seasoned developers can learn new techniques, approaches, or language features from their peers during the review process.

Code Review to Foster Team Collaboration

• Unified vision: By collaboratively reviewing code, team members align their understanding and vision of the project. This alignment helps in achieving project objectives more efficiently.
• Open communication: Code reviews provide a structured platform for open communication. Developers discuss, debate, and iterate on code changes, fostering a culture of constructive feedback.
• Builds trust: When team members review and learn from each other, it cultivates mutual trust and respect. This trust is essential for a healthy and productive team environment.

Code Review to Ensure Code Maintainability

• Consistency: Code reviews help maintain a consistent coding style and structure across the codebase. Consistent code is easier to read, understand, and modify.
• Detect code smells: "Code smells" are indications that certain parts of the code might be problematic in the future, even if they aren't causing immediate issues. Code reviews can help identify and address these early on.
• Documentation: Reviewers can highlight areas where comments or documentation might be lacking or unclear. Proper documentation ensures that future developers can understand and modify the code without undue difficulty.

In essence, code reviews serve as a multifaceted tool in software development. They not only ensure that the software is of high quality but also play a pivotal role in team dynamics, knowledge dissemination, and the long-term health of the software project.

The Code Review Process

The Code “Pre-Review”

Before submitting code for review, there are several preliminary checks and actions that can be taken to streamline the review process:

• Local testing: The developer should run the code locally to ensure that the changes work as expected and that no obvious bugs are introduced.
• Linting: Linters are tools that automatically analyze code to detect various issues, mostly related to style and formatting. Running a linter ensures the code conforms to the established coding standards. Examples include ESLint for JavaScript, Pylint for Python, and RuboCop for Ruby.
• Static analysis: Static code analysis tools examine code without executing it to identify potential problems, such as logical errors, unused variables, or potential vulnerabilities. Tools like SonarQube, Coverity, and Checkmarx are popular static analysis tools.
• Unit tests: If applicable, new or modified unit tests should be written to cover the changes. All tests, including existing ones, should be run to ensure nothing is broken.
• Commit message: Proper commit messages should be written to provide context about the changes, making it easier for reviewers to understand the rationale behind them.

To monitor the code pre-review process, you can leverage:

The Coding Time Metric

The Coding Time metric measures the time elapsed between start of development (either the first commit or PR creation date) and the review initiation. This time includes the coding time, the automated testing phase as well as the review pick-up time. 

The Commit Keyword Usage Report

The Commit Keyword Usage Report provides an overview of the first keyword used in each commit message. This report can help classify reviews by priority and ensure proper naming conventions are followed across team members.

The Main Code Review (Manual Inspection)

Once the code is ready and submitted for review, the core phase of the review process begins:

• Assign reviewers: Based on the nature of the changes and the codebase's area, appropriate reviewers are assigned. These could be peers, senior developers, or domain experts.
• Review for logic and design: The reviewers evaluate the submitted code for its logic and design, ensuring it's efficient, clean, and follows established architectural patterns.
• Feedback and discussion: Feedback is provided, usually in the form of inline comments on specific lines of code or general comments about the entire set of changes. The developer and reviewers can then discuss, clarify doubts, and iterate on the feedback.
• Multiple rounds: Often, the code review process involves multiple rounds where the developer makes revisions based on feedback, and reviewers inspect the changes again until all parties are satisfied.

To monitor the main code review process, you can leverage:

The Review Time Metric

The Review Time Metric calculates the time elapsed between the first submission review and the PR approval. 

The Pull Request Review Ratio

With the Pull Request Review Ratio , you can ensure that all PRs get the minimum required reviews.

The Average PR Size Metric

With the Average PR Size Metric , you can track the volume of code line changes (deletions + additions) performed on PRs, ultimately isolating big PRs likely to cause delay in both coding and review time.

Post-Code Review Actions

After the review process is concluded:

• Merging: Once the reviewers approve the changes, the code can be merged into the target branch (often the main or master branch).
• Continuous integration: After merging, the code often goes through a continuous integration (CI) process where automated tests are run, and the application is built to ensure there are no integration issues.
• Follow-ups: Sometimes, during the review, certain topics might be flagged for further discussion or exploration but aren't deemed critical enough to block the current changes. These can be noted as "follow-up" items. They might result in new tasks, tickets, or further reviews in the future.
• Document learnings: Any significant insights, common pitfalls, or best practices that emerged from the review can be documented. This helps to refine the development and review process for future tasks.

Remember, the exact steps and tools in a code review process might vary based on the team's preferences, the nature of the project, and the tools in use. The essence, however, remains largely consistent: to collaboratively ensure that code changes are of high quality and align with the project's goals.

To monitor the post-code review process, you can leverage:

The Merge Time Metric

The Merge Time Metric calculates the average time elapsed between last review approval to the PR merged into a specific branch. It helps isolate the post-review cycle time, ensuring that approved PRs are not forgotten in the process.

The Green Build Ratio Metric

The Green Build Ratio Metric helps ensure that the merged PRs have a green build status.

Code Review Best Practices

Adopting code review best practices is pivotal in cultivating a constructive, efficient, and collaborative software development environment, ensuring not just the quality of code but also fostering continuous learning and teamwork. Let’s dive into it.

Code Reviews Start with a Positive Tone

Why: Setting a positive tone encourages a collaborative and receptive atmosphere. It ensures that feedback is perceived as constructive rather than critical.

How: Begin your comments by acknowledging the effort or aspects of the code that you found well-done before pointing out areas of improvement.

Be Specific in Your Code Review Feedback

Why: Vague feedback can be confusing and might not lead to the desired improvements.

How: Point out specific lines or sections of code when giving feedback. Instead of saying, "This method is too complex," you might say, "Consider breaking down this method into smaller functions for better readability."

Limit the Scope of Code Reviews

Why: Extremely large code reviews can be overwhelming and decrease the chances of catching issues.

How: Encourage developers to make smaller, more frequent pull requests. If a large review is unavoidable, consider breaking the review into parts or sections.

Use a Standardized Checklist for Your Code Reviews

Why: A checklist helps ensure consistency across reviews and reminds reviewers of common issues to look for.

How: Create a list of items to check during every code review, like ensuring new methods have comments, checking for potential security vulnerabilities, or verifying the presence of tests for new features.

Prioritize Automated Tests Before Code Review

Why: Automating tests can catch a plethora of issues before human review, allowing the reviewers to focus on the logic and design.

How: Ensure that a CI (continuous integration) pipeline runs unit tests, integration tests, linters, and static analysis tools before the code is reviewed by humans.

Avoid Code Review Bikeshedding (Focus on the Big Issues)

Why: Engaging in prolonged debates about trivial matters can divert attention from more pressing issues and delay the review process.

How: Focus on the core logic, design, and potential impact of the code changes. If discussions start to veer off into minor style or preference debates, steer them back or defer those discussions for later.

Perform Code Reviews Regularly and Promptly

Why: Timely feedback is more relevant and allows developers to address issues while the context is still fresh.

How: Allocate specific times during the day or week for code reviews. Using tools that notify reviewers when a review is requested can also help in timely reviews.

Always Provide Context for Your Code Review Feedback

Why: Context helps the author understand the reasoning behind the feedback, making it more actionable.

How: Instead of just pointing out an issue, explain why it's an issue. For instance, rather than saying, "Avoid using global variables," you might add, "Global variables can introduce unintended side effects and make the code harder to maintain."

Remember to Review the Code, Not the Coder

Why: Code reviews should be a critique of the work, not the individual. Making it personal can lead to defensiveness and conflict.

How: Frame feedback objectively. Avoid using personal pronouns. For example, say, "This method can be refactored for clarity," instead of "You wrote a confusing method."

Implementing these best practices can greatly enhance the effectiveness of code reviews, promote a positive and collaborative team culture, and ultimately lead to better software quality.

Common Pitfalls in Code Reviews and How to Avoid Them

Overly Critical Code Review

When a reviewer focuses solely on flaws and expresses feedback in a harsh or negative manner, it can demoralize the developer, breed defensiveness, and inhibit productive dialogue.

• Start with positive feedback.
• Frame critiques as suggestions or questions.
• Use neutral language, focusing on the code and not the coder.

Don'ts:

• Avoid personal or pointed language.
• Don't make assumptions about the coder's intentions or capabilities.
• Avoid being overly pedantic on non-critical issues.

Skipping the Code Review Due to Time Constraints

Rushing through or completely skipping a code review due to time pressures can lead to undiscovered bugs, design flaws, or inefficiencies making their way into the production code.

• Set aside dedicated time for code reviews in the development cycle.
• If pressed for time, prioritize reviewing critical components or areas with substantial changes.
• Encourage smaller, more frequent pull requests for easier reviews.
• Don't make a habit of bypassing reviews.
• Avoid merging code without at least one review.
• Don't let "deadline pressures" compromise the quality of the codebase.

Not Checking for Potential Security Vulnerabilities During Code Review

Overlooking potential security issues during code review can lead to vulnerabilities in the application, risking data breaches, and other malicious attacks.

• Familiarize yourself with common security vulnerabilities (like those in the OWASP Top 10 ).
• Check for proper data validation, authentication, and authorization mechanisms.
• Ensure sensitive data is protected, encrypted, or redacted.
• Don't assume that external libraries or third-party code is always secure.
• Avoid leaving debug or test code that could expose sensitive data or functionality.
• Don't neglect potential red flags even if they seem minor.

Relying Too Heavily on Tools Without Manual Checks 

While automated tools (linters, static analysis, etc.) are invaluable, they cannot catch every issue, especially those related to logic, design, and contextual understanding of the application.

• Use tools as a first pass to catch common or straightforward issues.
• Always perform manual reviews to assess logic, design patterns, and application-specific nuances.
• Combine insights from tools with human judgment and expertise.
• Don't blindly trust tool results without understanding their output.
• Avoid treating tools as a complete substitute for human review.
• Don't ignore tool warnings without valid reasons.

In essence, while code reviews are instrumental in maintaining and enhancing the quality of code, avoiding these pitfalls is essential to ensure that the process remains constructive, efficient, and effective.

Tools and Platforms for Streamlined Code Reviews

Software development analytics to monitor and improve the code review process.

Tools like Keypup provide insights into the software development process, capturing metrics like cycle time, review time, reviews volume and frequency, pull request sizes, and more, to inform and improve development practices.

How to leverage Keypup for the code review process:

• Monitor key metrics to identify bottlenecks or inefficiencies in the development and review process by leveraging the Cycle Time Dashboard .
• Use historical data to track improvements over time and gauge the impact of changes to the development process.

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Leverage code collaboration tools to manage code reviews efficiently.

Code collaboration tools such as GitHub, GitLab, or Bitbucket provide integrated environments for hosting code repositories, creating pull requests, and conducting code reviews.

How to leverage code collaboration tools for the code review process:

• Utilize pull request (or merge request) features to initiate code reviews.
• Make use of integrated comment systems for inline feedback.
• Use built-in integrations with CI/CD tools to automatically run tests before reviews.
• Take advantage of platform-specific extensions or plugins for enhanced review capabilities.

Use Linting and Static Analysis Tools to Accelerate the Code Review Process

Linters and static analysis tools scan the codebase for syntactical errors, stylistic issues, potential bugs, and even security vulnerabilities without executing the code.

How to leverage linting and statics analysis tools for the code review process:

• Integrate these tools into the development environment or CI/CD pipeline to catch issues early.
• Customize rule sets based on the team's coding standards and guidelines.
• Use the tools as an initial filter before manual code reviews to focus on logic and design issues.

Use Continuous Integration and Deployment Tools (CI/CD) to Facilitate the Code Review Process

CI/CD tools such as Jenkins, Travis CI, CircleCI, GitHub Actions, and GitLab CI/CD, automate the building, testing, and deployment of applications, ensuring that the code integrates well and passes all tests before deployment.

How to leverage these tools in your code review process:

• Set up automated build and test pipelines to run whenever code is committed or a pull request is created.
• Integrate linting and static analysis tools within the CI process.
• Use CI results as a prerequisite for manual code reviews, ensuring only code that passes automated checks is reviewed.
• Implement automated deployment for code that passes both automated and manual reviews.

Incorporating these tools into the code review process not only streamlines the workflow but also ensures consistent code quality, reduces manual review burden, and fosters a culture of continuous improvement.

Concluding Thoughts: Measuring for Success in the Code Review Process

In the dynamic world of software development, code reviews stand out as an invaluable practice, enabling teams to collaboratively refine and enhance code quality. As we've explored, the right methodologies, tools, and a proactive approach can make this process effective and efficient.

However, it's crucial to remember that what gets measured gets improved. With platforms like Keypup, teams can gain actionable insights into their software development process, honing in on metrics that truly matter. By consistently monitoring cycle times, review durations, pull request sizes, and other key indicators, developers and managers can quickly identify and address bottlenecks, optimizing every phase of the Software Development Life Cycle (SDLC), including the critical code review step.

In essence, while tools, best practices, and collaboration play central roles, it's the strategic measurement and continuous improvement that truly set apart great development teams. As you embark on or refine your code review journey, always keep metrics at the forefront, ensuring that your efforts align with the overarching goals of delivering high-quality software in an agile and responsive manner.

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Building a Winning Code Review Process: 4 Tips for Success

Understanding the Code Review Process 

The code review process involves examining source code to identify potential issues, bugs, or areas that require enhancement. This collaborative approach not only aids in maintaining high-quality code, but also promotes knowledge sharing among team members. Carrying out regular code assessments enables developers to learn from one another and ensures their projects adhere to best practices .

Why are Code Reviews Important?

Here are a few reasons code reviews can be important for your software project:

• Quality assurance: Detecting errors early in the development cycle reduces the cost and effort needed to address them later.
• Maintainability: Upholding consistent coding standards simplifies understanding and modifying the work in the future.
• Knowledge sharing: Collaborative discussions during reviews facilitate the spread of domain-specific knowledge across the team.
• Cross training: Developers who engage in reviewing others' work gain exposure to various techniques, patterns, and approaches they might not have encountered otherwise.

Learn more in our detailed guide to code review for security (coming soon)

Key Elements of an Effective Code Review Process

An efficient code review process comprises several crucial elements that contribute to achieving its objectives. These include:

• Choosing suitable reviewers: Opt for reviewers with diverse skill sets and backgrounds within your organization to maximize learning opportunities and ensure impartial feedback.
• Prioritizing essential sections of the project: In large-scale projects with limited time for comprehensive reviews, prioritize the most critical sections that are more likely to contain errors or affect overall functionality.
• Establishing clear expectations: Set guidelines for reviewers, such as concentrating on particular areas of concern, providing constructive feedback, and meeting deadlines.
• Promoting open communication: Cultivate an environment where team members can openly discuss their concerns and suggestions without fear of judgment or retaliation. Encourage developers to ask questions and request clarification when necessary.

Incorporating these elements into your code review process can help ensure it is both efficient and effective in achieving its goals. By fostering collaboration, learning opportunities, and adherence to best practices within your development team, you'll be well on your way towards creating high-quality software.

Related content: Read our guide to code review checklist

Popular Code Review Processes 

Email threads.

Email threads were once a common method for developers to conduct code reviews. A developer would send an email containing the changes made in the source code along with explanations or questions about those changes. Team members would then respond with feedback via email replies.

• Pros: Easy to implement; no additional tools required; asynchronous communication allows flexibility in response times.
• Cons: Can become disorganized quickly; difficult to track multiple threads of conversation; not ideal for large teams or complex projects.

Pair Programming

In pair programming, two developers collaborate on a single task at one workstation. One person writes the code while the other observes and provides real-time feedback on design decisions, potential bugs, or improvements needed.

• Pros: Immediate feedback leads to faster resolution of issues; promotes knowledge sharing among team members; helps improve overall coding skills through collaboration.
• Cons: Requires both participants' full attention simultaneously; can be time-consuming; may not be suitable for all team members or tasks.

Over-the-Shoulder

Over-the-shoulder code review is an informal approach where one programmer requests another to check their modifications while explaining the thought process behind them. This method encourages face-to-face communication and allows for immediate feedback on potential issues.

• Pros: Fosters collaboration and knowledge sharing; quick and easy to implement; builds strong working relationships among team members.
• Cons: Limited in scope due to its informal nature; heavily relies on individual expertise, which may vary across the team.

Tool-Assisted Review

In a tool-assisted review process, developers utilize specialized software that enable code visualization, collaboration, version control, or change tracking. These tools often provide features such as inline commenting, automated testing integration, and visual representations of code changes over time.

• Pros: Streamlines the review process by centralizing discussions around specific lines of code; supports asynchronous communication allowing flexibility in response times; integrates with existing development workflows through plugins or APIs (e.g., Git).
• Cons: Requires learning new tools/software; may require additional setup or configuration depending on the chosen tool.

4 Tips for a Successful Code Review Process 

1. implement code review metrics.

Introducing code review metrics is crucial for monitoring the effectiveness of your code reviews. Some valuable metrics include:

• Average time spent on each review
• Total number of issues found per review session
• The ratio of accepted suggestions to total suggestions made by reviewers
• The percentage of defects fixed before deployment due to code reviews

Collecting these data points allows teams to pinpoint areas that need improvement and make informed decisions about optimizing their code review process.

2. Discuss High-Level Approaches Early On

To prevent misunderstandings or wasted effort during the coding phase, it's vital for project team members to engage in early discussions about high-level approaches. 

These initial conversations enable the team to ensure all members are on the same page regarding what needs to be achieved and how it should be done, while avoiding personal preferences or coding standards. The sooner these discussions occur, the smoother your development cycle will be.

3. Focus on Coding Standards, Not Personal Preferences

A crucial aspect of any successful code review is concentrating on adherence to established coding standards rather than personal preferences. This ensures consistency across projects while minimizing conflicts between team members who may have differing opinions regarding style or syntax choices. Linters are automated tools that can help enforce these standards automatically.

4. Offer Constructive Feedback

Instead of merely highlighting issues, reviewers should strive to provide constructive feedback that aids developers in improving their code. This means offering specific suggestions for enhancement and explaining the reasoning behind them. Providing constructive input on code not only raises its quality but also fosters a positive learning environment within the team.

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How To Review Someone Else’s Code: Tips and Best Practices

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Imagine you have a co-worker or friend who’s asked you to review a piece of code for them. You might be thinking, “Wait, I don’t really know what that means.” Maybe you’re too nervous to say that to your colleague. Not to worry — we’ve all been there.

While your first code review might seem like yet another test of your abilities, it’s actually just another set of eyes on a piece of code to help spot any problems before it gets launched. Even if you’re a new developer or still learning code, you can help people out by reviewing their code.

In the following article, we’ll help to demystify what it means to review code . We’ll even lay out a five-step process to follow so you can review someone else’s code easily and clearly. Check out the video below. Then read on to learn more.

What is a code review?

A code review is a collaborative process where other members of your development team look over your code to give you:

• Potential improvements
• A list of outstanding questions

In practice, this means that your fellow developers will either add comments within your code or send you a list of questions to answer. They could also sit down with you at your computer and talk through a few suggestions on how to make your code better. It’s a good idea to ask someone who will eventually use the code to help you review it.

Why is it a good idea to review code?

Reviewing code helps maintain best practices for the code and keep a certain standard across the code base. Elements of the code, including styling, formatting, design patterns, and naming conventions, should be kept consistent. Having someone who works with the same standards review your code will help keep it formatted correctly and easy to use for other team members.

Code review is also a great way to introduce other team members to the new piece of code going into the code base. You can talk about it and get them up to speed quickly.

Additionally, it helps to minimize or eliminate the “bus factor,” which Mike, the developer from Philadelphia who talks about code review in the video above, describes:

“The bus factor refers to the problem of having one team member with too much knowledge. The problem is if that team member then got hit by a bus, then no one on the team would know about the code that’s going into the code base.”

Lastly, a code review is a good idea because it facilitates discussion. When teams are busy or working remotely, communication doesn’t happen as frequently. Scheduling code reviews is a great way to get teammates talking, strategizing, and learning from one another.

Where do code reviews happen?

Depending on your relationship with the person asking you to review their code, this could happen in several locations. For example, a fellow learner or programmer friend of yours could simply email you a code file and ask for your comments. In that case, you would put your comments in the code file and send back any questions you have in an email response.

Alternatively, a code review can happen online with a community of programmers. You can help review someone else’s code on websites like:

• Codecademy Forums

If you take part in a code review on some of these repositories (like Stash or Github), it’s done with a pull request. The original programmer will add you as a reviewer, and then the website will track all changes that you make when you’re completing your code review. You could also be conducting a code review internally at work, either in person or using a version control system that your company has implemented.

5 easy steps to a successful code review

To help you get started with reviewing code, we’ve got a simple five-step process to share. Let’s get into code review best practices.

1. What is the code doing?

To start, we need to determine why the code was written in the first place. For example, if you’re conducting a code review at work, the purpose of the code could be tied to a change in requirements. It’s key to know the purpose of the code because that context will allow you to deliver the best possible code review with helpful comments.

To make sure that you have a good understanding of what the code is for, here are three questions you can ask yourself (or your fellow programmer):

• Do you have the right background info?
• Do you fully understand why this code is needed?
• Do you understand how this code fits into the project?

2. Frame your mindset

Before you get started reviewing the code, you want to get into the right mindset. In a sense, you want to know how you fit into this scenario. What is your level of familiarity with the code? How confident are you in knowing the person who’s written the code and what they are trying to accomplish? This will give you an idea of what feedback you can confidently give to this author.

This step might sound a little vague, so we’ve got a list of questions to help you set up your mindset for the code review:

• How experienced are you with the codebase or language?
• Are you going to be using this code in the future?
• Have you written code similar to this?
• What is the experience level of the author?
• What is your relationship with the author?

3. Test the code

Now that we know what the code is for, we can go ahead and test it out. We’re looking to see if the code does what it’s supposed to do. During this step, you can also test out the user interface. For example, if you’re reviewing a website, you could check to make sure that it appears as it should, that the changes are incorporated, and that nothing breaks as you use it.

If you need a couple of questions to help you provide feedback on code function, you can start here:

• Does the code generate warnings or errors?
• Does the code take longer than normal to build or run?
• Do the changes require any additional setup steps?

4. Inspect the code

After figuring out if the code actually works, we can dive into the code itself and make sure it’s written well. Here, we’re getting into the details of code review best practices. You can offer up advice on how things might be better organized or formatted. For example, you could ask yourself:

• Are correct naming conventions followed?
• Does the code follow DRY principles (i.e., it doesn’t repeat itself)?
• Are new files and folders named appropriately?
• Does the code have error handling?
• Is the code written in a style that’s similar to any other code within the same project?

5. Compile your review

Just as the code review can take place in several locations, you can also format your code review in a variety of ways. Sometimes you might need to prepare a formal report of your findings and then submit that as a Word document or PDF.

In other situations, if you are using a website like GitHub, you may just add comments to the code. If you have longer questions or feedback, you can add them to a comment thread and allow the conversation to take place all online.

Keep in mind a few tips when you are compiling your code review:

• Beware of nitpicking
• Be respectful
• Be specific and descriptive
• Be open to follow-ups

Growing as a developer through code review

One of the great things about becoming a developer or learning some aspects of programming for yourself is that you get to learn and work with other people. Code reviews are a common practice, and the discussion they generate will help make you a better programmer, whether it’s your code being reviewed or someone else’s code.

“Coding is a team sport,” says Mike. Learning to code should be fun, and learning how to give great code reviews is part of the process. If you’re thinking of becoming a front-end engineer or a back-end engineer , code reviews are a great way to practice for your new job.

To learn more of find other learners to practice with, head over to the Codecademy Forums .

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eng-practices

How to do a code review.

The pages in this section contain recommendations on the best way to do code reviews, based on long experience. All together they represent one complete document, broken up into many separate sections. You don’t have to read them all, but many people have found it very helpful to themselves and their team to read the entire set.

• The Standard of Code Review
• What to Look For In a Code Review
• Navigating a CL in Review
• Speed of Code Reviews
• How to Write Code Review Comments
• Handling Pushback in Code Reviews

See also the CL Author’s Guide , which gives detailed guidance to developers whose CLs are undergoing review.

• Case studies
• Solutions ecosystem & architecture

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Emil Waszkowski

If you’ve been struggling with poor app performance, you might want to consider outsourcing code review. Here’s what the code review process is all about.

Regular code reviews prove to be an important part of the software development process. While automated tests, peer reviews and quality assurance can catch mistakes, mistypes, architectural flaws and some other limitations - in many cases, only a fresh pair of eyes can assess whether the design, logic, and quality of the code are up to standard.

If your existing app is not performing as fast and seamlessly as it should, or you’ve been struggling to add any new features for some time now - it’s high time to think about outsourcing code review and consider implementing regular reviews in the future to avoid such issues (if you haven’t already).

Here’s why code reviews matter and how to do them properly, either in-house or with some help from an experienced software development company like us. First things first, however:

What is code review?

Like any other human creation, software is prone to mistakes. With code reviews, however, these mistakes can be kept to a minimum.

Essentially, code review is the process of assessing code and its quality to find areas for improvement or code smells, as well as to identify bugs, errors, and part of the code that might not be up to quality standards set by the organisation.

Usually, it’s the fellow programmers who check each other’s code for mistakes, but the code review process can also be performed by a specialised software development company, especially if you plan to hire one.

Why code review?

It might not seem like it at first, but regular code reviews are capable of streamlining and accelerating software development like no other. A while back, the Best Kept Secrets of Peer Code Review already revealed the following benefits:

• Improved code quality
• Fewer mistakes in the code
• Shorter development and test cycles
• Increased user satisfaction
• Reduced impact on technical support

Since then, however, there are a few other code review benefits that can be added to the list. In fact, having a fellow developer reviewing code is said to be the most effective way to find and eliminate problems while coding nowadays.

When done right, code reviews streamline development, save time, the amount of work needed from Quality Assurance teams, and often money in the long run. What’s also worth taking into account is that regular code reviews contribute to the sense of "ownership" for any piece of code that developers write, and serve as a great opportunity to learn for more junior members of the team

Given these benefits, it shouldn’t come as a surprise that code reviews are seen as a valuable part of the software development process by many product owners. The truth is that any team can benefit from code reviews, regardless of technology and development methodology in place. Let’s take a closer look at how to review code, then.

How does code review work?

As with any other important piece of the puzzle, code reviews should integrate with the existing software development process. If you plan to initiate code reviews in your organisation, you should start by deciding who would be involved in it in the first place.

There are different ways in which code reviews can be performed:

• Notifying all software developers in the team. Once a given piece of code is ready for review, it’s sent around to all available software developers. Whoever will have some time for it first, they are going to review the code. This approach certainly allows for more flexibility, but since there’s no specific person responsible for the code review, it might not be done in the end.
• Leveraging pair programming. This approach makes two developers working on the same code together and checking each other’s work. But, since both of them are kept close to the code, they might be subjective at times. Not to mention that pair programming also requires more resources (time & team members) than some other methods.
• Having specific senior developers/team leaders involved in the code review process. This “over-the-shoulder” method is one of the easiest ways to perform a code review. Once the piece of code is ready, developers should have a specific colleague assigned (the more senior, the better) to review their work. This can either be done remotely or in-person.

When doing code reviews “in-house”, it’s also important to decide on timelines, iterations, and requirements for submitting code for review. Once you get that covered, you should familiarise your development team with the code review process and make sure it gets implemented properly.

What to look for when performing a code review, then?

When doing a code review, there are different factors that should be taken into account:

• Requirements : Are all cases fully implemented?
• Purpose : Is there a reason for every change made by the developer?
• Logic : Are there any obvious logic errors in the code?
• Design : Is the code well-designed?
• Functionality :  Is the way the code behaves good for its users?
• Complexity : Could the code be made simpler?
• Tests : Are the automated tests sufficient for the code?
• Style : Does the new code conform to existing style guidelines?
• Documentation : Was the relevant documentation updated?
• Naming : Are the names for variables/classes/methods clear enough?
• Comments : Are the comments concise and useful?

The exact criteria might change, but the aim stays the same: no matter the code review process you have in place, it’s crucial to review every new line of code, aim to improve its quality and help developers to get better at coding in the long run. In case you need some more guidance, here’s a set of best practices in code reviews.

Code review - best practices

• Establish what to look for in code reviews. As already mentioned, there are at least a few important criteria to keep in mind when performing code reviews. Set your standards and make sure your code reviewers follow them every time.
• Test thoroughly before reviewing the code “manually”. Time is of the essence - don’t waste it on tasks that can be automated. Ideally, you’d perform the review after code passes the automated checks, and then deploy it. This approach will allow you to cut down on errors and save time in the code review process.
• Keep it short (relatively). Research shows that after spending 60 minutes on code reviews, performance and attention to detail are not as sharp. The best practice seems to be reviewing between 100 and 300 lines of code at once, and spending 30-60 minutes on it every single time.
• Give constructive feedback. This should go without saying, but being constructive rather than critical in your feedback is essential to keep the team morale high and continue to learn from mistakes made. Code reviews play an important role in software development, which is why it’s crucial to foster a positive experience around them.
• Have a process for drawing conclusions and fixing the code. Identifying bugs is one thing, but fixing them is a different story. It might seem obvious but many development teams don’t have the process in place for fixing the issues they discovered. Make sure it’s not the case with your team.

Code review as a service

With existing software, you also might want to check the quality of the code and efficiency of the chosen technology up till now. In such cases, getting a fresh pair of eyes and outsourcing code review is a common practice.

Code reviews performed by external specialists make it possible to assess the used technology and written code in terms of efficiency, scalability, usability, costs and further development. It comes in useful especially when you plan to grow your product or outsource its development to a different team.

There are a few other benefits that stem from outsourcing code review, though:

• Outsourcing code reviews to developers who actually specialise in them can bring your business much better results. Programming skills don’t always translate into reviewing skills, which is something to keep in mind.
• Outsourced code review presents an unbiased, third-party perspective. Rather than taking into account who exactly wrote the code, an external team of specialists focuses solely on the code and its quality.
• Outsourcing code review can help you avoid technical debt. Being proactive about code quality can save you a lot of money and time in the long run. Actually, research shows that technical debt and maintenance issues can consume even 42% of a developer’s time, which should be a good enough reason to outsource code reviews every now and then.

How do we perform code audits at Future Mind

At Future Mind, we have an experienced team of developers who create complex solutions for a range of industries , including retail and insurance applications that have to be compliant with the highest standards, scalable, and able to serve millions of users. Code reviews are an important part of the whole process - and we perform them for clients with existing products as well.

As a matter of fact, when reviewing an existing product and its code, we check the quality of the software, the architecture, and app efficiency to evaluate usability, scalability, and the potential for changes and further development. The results of our review are presented in a comprehensive audit report, along with improvement recommendations.

In a nutshell, Future Mind’s audit report includes the evaluation of:

• App architecture
• The correct use of chosen technology and libraries
• Review of the core source code fragments based on style, standards and best practices
• Code performance & efficiency
• The scalability of the source code
• The quality and reliability of the software development process
• The quality of the automated tests: their scope & coverage
• The clarity & readability of the code, and the easiness with which new team members can be onboarded
• Findings & recommendations

The whole code review process takes approximately 2 weeks and is performed by a senior developer.

Since code review is a fast method for checking the efficiency and quality of the existing source code, as well as evaluating its potential for growth - you might want to consider it when your app users report bugs and low performance, or you simply want to find out whether the app is being developed with the highest standards and best practices in mind.

In both cases, you can turn to software development specialists for a comprehensive code review. As usual, we’re here to help .

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Code Review Best Practices and Process: Elevating Code Quality and Team Efficiency

In today’s dynamic software development landscape, maintaining high-quality code is crucial for delivering robust and reliable software. One effective approach is implementing a well-structured code review process. This practice not only ensures code quality but also promotes knowledge sharing and collaboration among development teams. In this article, we’ll delve into the best practices for a code review best practices and process, integrating thought leadership insights, and practical advice for enhancing your development workflow.

Understanding the Code Review Process

A code review process is a systematic examination of code changes by team members other than the author. The primary goals are to identify defects, ensure adherence to coding standards, and foster a culture of continuous improvement. For a software development company aiming to excel, refining the code review process can significantly impact the overall success of projects.

Why Code Reviews Matter

Before diving into best practices, it’s important to understand the impact of code reviews:

• Quality Assurance: Catching bugs and issues early in the development cycle saves time and resources in the long run. Early detection of defects ensures that problems are addressed before they escalate, leading to more stable and reliable software.
• Knowledge Sharing: Junior developers learn from senior colleagues, while experienced developers stay updated with evolving coding techniques. This ongoing exchange of knowledge and expertise strengthens the team and encourages professional growth.
• Consistency: Code reviews enforce consistent coding standards across the team, making the codebase more maintainable. Adhering to common guidelines ensures that the code is easier to read, understand, and modify, reducing the likelihood of errors.
• Team Collaboration: Promotes a culture of open communication and collaboration, essential for a cohesive development team. By facilitating constructive feedback and discussion, code reviews help team members align their efforts and improve overall productivity.

Best Practices for Code Review Process

Code reviews are a cornerstone for maintaining high-quality code and fostering a culture of continuous improvement. A well-structured code review process not only enhances code quality but also boosts team collaboration, knowledge sharing, and adherence to best practices. By systematically examining code changes, teams can identify potential issues early, ensure compliance with coding standards, and promote best practices throughout the development lifecycle. To maximize the effectiveness of code reviews, it’s essential to implement a set of best practices that streamline the process and align it with the team’s goals and objectives. Here are some fundamental practices to consider for an effective and efficient code review process:

Define Clear Objectives

Setting explicit objectives for your code review process is crucial for aligning the team’s efforts and expectations. Objectives provide direction, ensuring that reviews are purposeful and focus on achieving specific outcomes. Common objectives might include enhancing code quality, ensuring adherence to security practices, improving readability, or fostering team learning. For example, if the goal is to enhance code readability, reviewers should concentrate on the clarity of the code and adherence to established style guides. This clarity in purpose helps in systematically addressing areas that need attention and ensures that reviews are not just a formality but a constructive part of the development process.

Establish Coding Standards

Having a well-defined set of coding standards is fundamental to maintaining consistency and quality in your codebase. Coding standards should cover naming conventions, code formatting, documentation guidelines, and best practices for writing clean and efficient code. When all team members adhere to the same standards, the review process becomes more straightforward, as there is a common understanding of what constitutes good code. This shared framework helps avoid subjective disagreements and streamlines the evaluation, making it easier to focus on substantive issues rather than stylistic differences.

Automate Where Possible

Automation can significantly enhance the efficiency of the code review process by handling routine checks. Tools such as linters, static code analyzers, and Continuous Integration/Continuous Deployment (CI/CD) pipelines can automatically detect and flag common issues like syntax errors, style violations, and simple bugs. This allows human reviewers to dedicate their time and expertise to more complex and nuanced aspects of the code, such as architectural decisions, algorithmic efficiency, and potential security flaws. Incorporating automation reduces the manual burden on reviewers and increases the reliability and consistency of the review process.

Limit Review Size

Managing the size of code reviews is essential for maintaining effectiveness and reducing reviewer fatigue. Large code changes can be daunting and are more likely to result in overlooked issues. To facilitate more thorough inspections and quicker feedback cycles, aim to keep review sizes under 400 lines of code. Smaller, more frequent reviews make it easier to focus on details, provide timely feedback, and maintain a steady pace of development. This practice helps in identifying and resolving issues early, contributing to overall code quality and developer productivity.

Foster a Positive Review Culture

Cultivating a constructive and respectful environment for code reviews is critical for team morale and collaboration. Reviews should focus on the code, not the coder, and feedback should be delivered in a positive, supportive manner. Emphasizing constructive criticism and recognizing good practices can help mitigate defensiveness and promote a culture of continuous improvement. Celebrating code quality improvements and providing positive reinforcement encourages engagement and motivation, making the review process a positive experience rather than a punitive one.

Prioritize Critical Code Sections

Not all code requires the same level of scrutiny. Identifying and prioritizing critical sections of the codebase, such as those related to security, performance, or complex algorithms, ensures that the most significant areas receive the necessary attention. By focusing on high-risk or high-impact areas, you can mitigate potential issues that could have serious implications for the project. This targeted approach helps in allocating review efforts efficiently, ensuring that critical aspects are thoroughly examined and potential problems are addressed proactively.

Provide Actionable Feedback

Effective feedback is specific, constructive, and actionable. Instead of vague comments like “this isn’t good,” provide detailed suggestions on how to improve the code. Actionable feedback helps developers understand the issues and learn from the review process, fostering a culture of growth and continuous improvement. Providing examples, references to best practices, and clear explanations can guide developers in making the necessary changes effectively, enhancing both the quality of the code and the skills of the team.

Implement a Review Checklist

A review checklist standardizes the code review process and ensures that common issues are consistently addressed. Checklists can include items such as code readability, adherence to coding standards, testing coverage, potential security vulnerabilities, and performance considerations. Having a checklist serves as a useful guide for reviewers, helping them focus on key areas and ensuring that important aspects are not overlooked. This structured approach promotes thorough and comprehensive reviews, leading to more reliable and maintainable code.

Balance Speed and Thoroughness

Balancing the speed and thoroughness of code reviews is crucial for maintaining both quality and efficiency in the development process. Quick reviews help keep the development cycle moving smoothly, but they should not come at the expense of thoroughness. Establish a protocol that allows for timely reviews while ensuring that critical aspects are examined in detail. Allocating dedicated time for in-depth reviews, especially for complex or high-impact code changes, can help achieve this balance, ensuring that quality is maintained without causing significant delays.

Encourage Pair Programming

Pair programming, where two developers work together on the same code, can complement traditional code reviews by fostering real-time collaboration and immediate feedback. This approach can lead to higher code quality and faster issue resolution, as it allows for immediate discussion and problem-solving. Pair programming also facilitates knowledge sharing and skill development, enhancing both the code and the capabilities of the developers involved. It can be particularly effective for complex or critical code areas, where collaborative problem-solving can lead to better outcomes.

Continuous Improvement

The code review process should be dynamic and evolve over time. Regularly assess the effectiveness of your review practices, gather feedback from the team, and make adjustments as necessary. A continuous improvement approach helps the team adapt to changing requirements, new technologies, and evolving best practices. By learning from past reviews and refining the process, you can enhance the overall efficiency and effectiveness of code reviews, ensuring that they continue to add value and contribute to better software quality.

Document Best Practices

Maintaining comprehensive documentation of the code review process, including best practices, tools, and guidelines, is essential for consistency and onboarding. Clear documentation serves as a reference for current team members and helps new developers understand and follow the review process effectively. It ensures that everyone is aligned with the established practices, contributing to better code quality and smoother collaboration. Documenting the process also facilitates the sharing of knowledge and best practices across the team, supporting continuous improvement and fostering a culture of excellence in code reviews.

Implementing Code Reviews in a Software Development Company

For a software development company , implementing a robust code review process is key to delivering high-quality solutions. Here’s how to integrate these best practices into your workflow:

• Tailor the Process: Customize the code review process to fit your team’s specific needs and project requirements. Consider factors such as team size, project complexity, and technological stack to develop a process that aligns with your goals.
• Use the Right Tools: Integrate tools like GitHub , GitLab , or Bitbucket with code review features to streamline the process. These platforms offer built-in review functionalities that can automate parts of the review and facilitate collaboration.
• Allocate Resources: Ensure that sufficient time and resources are dedicated to code reviews. This investment pays off in improved code quality and reduced technical debt. Allocating dedicated time for reviews helps prevent rushed evaluations and promotes thoroughness.

The Role of Code Reviews in Agile Development

In Agile development , code reviews play a critical role in maintaining flexibility and ensuring timely delivery of features. Here’s how they fit into the Agile framework:

• Regular Reviews: Conduct code reviews as part of the daily workflow, aligning them with the iterative nature of Agile. Integrating reviews into daily stand-ups or sprint cycles helps ensure that code quality is consistently monitored.
• Incremental Improvements: Focus on reviewing small, incremental changes, which aligns with Agile’s emphasis on continuous improvement. By addressing changes in small increments, you can manage complexity more effectively and respond to feedback swiftly.
• Cross-Functional Teams: In Agile, teams are cross-functional. Code reviews encourage collaboration across different roles, enhancing the overall quality of the product. This collaborative approach leverages diverse perspectives, contributing to more comprehensive reviews and better solutions.

Common Challenges and Solutions

Frequently Asked Questions

How often should code reviews be conducted.

Code reviews should be conducted regularly as part of the daily development workflow. Integrating reviews into the continuous integration and deployment (CI/CD) process ensures that code changes are consistently evaluated. This approach helps catch issues early and maintain a high standard of code quality throughout the development lifecycle.

What tools can help streamline the code review process?

Tools like GitHub, GitLab, Bitbucket, SonarQube, and ESLint can automate various aspects of the code review process, such as detecting syntax errors, style violations, and potential bugs, making the review process more efficient. These tools enhance the accuracy of reviews and reduce the manual workload on developers.

How can we handle conflicts during code reviews?

Address conflicts by focusing on objective criteria such as coding standards and best practices. Encourage open communication and collaboration to resolve differences and make decisions based on what’s best for the codebase. Facilitating discussions and seeking consensus can help overcome disagreements constructively.

What’s the ideal review size for code changes?

Ideally, keep code review sizes under 400 lines. Smaller reviews are easier to manage and less likely to miss issues compared to larger, more complex reviews. Breaking down changes into smaller increments makes reviews more manageable and allows for more focused and effective feedback.

How can we ensure junior developers benefit from code reviews?

Pair junior developers with more experienced reviewers who can provide mentorship. Encourage questions and discussions during reviews to facilitate learning and growth. Providing constructive feedback and educational resources can help junior developers understand best practices and improve their coding skills.

Implementing an effective code review process is essential for any company aiming to deliver high-quality software. By following these best practices, you can enhance code quality, foster team collaboration, and create a culture of continuous improvement. If you have needs related to IT or require expert advice on refining your code review process, consider reaching out to Savvycom, a top 10 IT provider in Vietnam and a trusted tech partner that delivers solutions valued for money. By integrating these best practices, your team can achieve greater efficiency and code excellence, positioning your company for long-term success in the competitive software development industry.

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Best practices for Reviewing Code

Best practices for reviewing code.

You can now consume the entire blog in an audio version. Give it a try.

What is code review.

Code review is a software quality assurance process in which software’s source code is analyzed manually by a team or by using an automated code review tool. The motive is purely, to find bugs , resolve errors , and for most times, improving code quality . Reviewing the codebase makes sure that every software or new feature developed within the company is of high quality. Code review is an essential process that every software company must follow, so we researched the best practices for reviewing code.

Did You Know?

On average developers spend over 17 hours per week dealing with maintenance issues like debugging and refactoring, and about a quarter of that time is spent fixing bad code. That’s nearly $300B in lost productivity every year. 

-According to a research conducted by Stripe in partnership with Harris Poll

Top 9 Practices for Reviewing Code

Let’s dive into the best practices for performing an effective code review . A code review process differs from team to team; it’s an approach that needs few changes according to the projects and members getting involved. We have listed below 9 points to keep in mind while analyzing your code.

1. Set goals and standards

Before implementing a code review process, it is imperative to decide on important metrics and define unambiguous goals. Goals include acceptable coding standards in the company. Having set standards makes sure that each software product developed in the company meets the company’s standards.

2. Communicate Goals and Expectations

Communication of goals and expectations is essential. Not conveying goals and expectations to everyone in the team can lead to ambiguity regarding the result. Knowing what is expected from a developer makes it easier for them to complete a task.

3. Define a Code Review Process

Now that the goals and expectations are set and communicated with everyone it is time to define a code review process. Having a defined code review process will help everyone stay on track and decrease the time spent on technical debt

4. Use a code review checklist

A good code review requires a well-defined checklist. This checklist can be used by the reviewer to make sure nothing is missed out.

Recommended Read: The Ultimate Code Review Checklist

5. Authors should annotate source code before the review

Annotation can be a useful tool throughout the software development cycle and also for the reviewer. It helps the code reviewer understand the code better and what each block of code does. We encourage developers to add annotations to their code but do not overdo it.

6. Review for no more than 60 minutes at a time

It is a well-known fact that a person’s efficiency can deplete if they try to work continuously for hours without taking a break. The same concept applies when trying to review code. It is not recommended to perform code reviews for more than 60 minutes. Research has stated that post the 60 minutes mark the reviewer’s efficiency can deplete can some of the defects that may go unnoticed.

7. Establish a process for fixing defects found

Fixing the defects post a code review process is an ultimate goal. Having a defined process to fix the defects will make sure that it is done in the most effective way and with the least technical debt.

8. Foster a positive code review culture

In many companies, code reviews are used to evaluate the developer’s performance. But code reviews should be used for more than that. It should be used to develop an environment of learning. Rather than just telling them their mistakes it should be seen that they learn how to solve them and make sure these are not repeated.

9. Automate to Save Time

Automated Code Review tools like Codegrip are great assets for every software company. Tools like these can help reduce code review times to a few seconds. They can scan the entire codebase in less than a minute and find defects and also provide solutions for them.

Reviewing code is only a matter of seconds with Codegrip. Detect all bugs and vulnerabilities with a click of a button.   Your browser does not support the video tag.

Best code review technique.

Every company has its own process of performing code review but we look into four of the best and most code review techniques. 

1. Instant Code Reviewing Technique

The most direct form of reviewing code is the Instant Code review technique. In this, the developer is writing code while the reviewer sits beside reading the code simultaneously and correcting it on the go. Also known as pair programming, this process is best suited for highly complex programs where two minds can solve the problem much quicker and efficiently.

While this process looks favorable for companies but in reality, the time and workforce needed by this technique make it unfavorable. Two or more people working on code together means fewer average lines per developer. Interruption for corrections also halts the flow of work for the author of the code and the learning curve for a developer hinders if constant support or solution is presented right away by a reviewer for a complex problem.

  2. Ad-hoc (synchronous) Code Reviewing Technique

Also known as the “Over the Shoulder” code-review process. It is the most commonly used process with around 75% of companies participating in ad-hoc reviews. In this type of synchronous method, the coder produces the code and then asks the reviewer to review the code. The reviewer joins the coder at the screen and reviews the code while discussing it, over the shoulder. It is implemented wisely because it is informal and spontaneous. The process is successful only if the reviewer is available at the time or it disrupts the coder’s speed.  

This method has a high probability of missing errors and glitches as most of the time, the reviewer lacks the knowledge of the goal of the task. Immediate review was missed to bring out better results as a team would have in their refinement sessions together with tasks discussed upfront.

The ad-hoc review usually results in only a developer knowing the goal of the project. The major problem of this process is forced context-switching. Imagine working on complex software yourself, and then being called by your junior member for an ad-hoc review. You would have to leave your station immediately to review the code of your co-worker. Having to leave your work suddenly can create exhaustion and frustration.

3. Meeting-Based Code Reviewing Technique

This is the least commonly used process with only 44% using it once a month. In meeting-based code review, coders complete their work, and a meeting is called. The whole tech team sits, commenting, and attempting to improve the code together. It is a temporary process as it is highly unlikely to perform constantly considering the amount of time, loss of workforce for the time, decreased efficiency, and inability to get the whole team together.

Meeting-based code reviews make sense only when the whole team is inexperienced with the code review process. It involves assembling the entire team in a room, sharing ideas, and solving problems a few times. This helps every team member to understand the process much more clearer. With just over half of the companies using this, this process is not adequate as a code quality assurance standard.

4. Tool-Based Code Reviewing Technique

This process is not done by a team together, at least not on the same screen. It is also called an asynchronous code review. In this, once the code gets finished, the coder makes it available for others to review. The reviewer will review the code on their screen commenting, or even amending the errors in the codes. Then notifying the coder who on her agenda will improve it. When there are no changes, the code is marked with no comments for improvements, and the software gets approved.  

Tool-based code review eliminates the major problem in the above two processes, direct dependencies. With both coders and reviewers working on their schedules, it also eliminates forced context switching. But just like any other method has its downsides, the tool-based technique has many review loops which take a lot of time just like meeting-based processes.

Discussing these processes, we realize that there’s a need for a method that can make the use of Tool Based Code Review and remove the indirect dependency to get faster results. The solution to this is Automated Code Review Tools.

60% of Developers are using automated tools; 49% are using them at least weekly.

Automated Code Review Tools are tools prepared by tech community experts and reviewers who love using tool-based techniques but need the quickness of the ad-hoc technique. We will refer to our tool, CodeGrip to explain how these tools work. CodeGrip connects directly to your repositories like GitHub or BitBucket and lets you import your repository. It analyses your code line by line, finding out error markers such as incorrect lines, duplicity , and security issues , and displaying it collectively for a project and separately for all files as well.

Here’s a video of how you can review your code using Codegrip

An automated code review eliminates the manual reviewer role in the process. CodeGrip also provides the developer with a suggestive engine that shows the suggestions to amend code line by line. Codegrip also shows the estimated time to correct the code, allowing the developers to schedule work accordingly. This process is faster, more efficient, and even highly feasible at any time of period.

Want to get accurate code review results? Sign up now and get instant code review reports for Free!

Code review has remained the trusted code quality practice for the past few years. It seems to continue for years to come. But issues like lack of time and manpower call for the rise in the use of Automated Code Review tools. They’re more powerful, easier to use, and in the case of Codegrip highly affordable too.

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Pranav mandhare

Well curated Content. The best practices are very apt for every software company. I loved that you also had an audio and video version of the blog.

Thank you. Stay updated new blogs are coming up every week.

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Local News | Business owners hail changes to Boulder’s…

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Local news | business owners hail changes to boulder’s ‘incredibly frustrating’ development review process.

The existing review process, which involves multiple steps and can require approval from city staff and boards, can be so long and arduous that one business owner described it as a “nightmare.” The city acknowledged in a staff presentation that the city’s use review process is a “significant barrier” for new businesses.

Matt Bernstein has owned a business in Boulder for more than eight years. He’s in the process of moving his gym, Ape Co Movement School, from its former location on Valmont Road to a new spot at 4745 Walnut St. But the process of getting the necessary permits and approvals from the city has dragged on for months.

First, Bernstein said, it took two months for the city to tell him he needed to add sprinklers inside the building. He had previously been told that sprinklers aren’t required for spaces less than 5,000 square feet (his space is just under that), and installing sprinklers would cost about $200,000. Bernstein also needed separate approvals for other changes, such as adding bathrooms, and he said it took weeks to get a response from the city on those.

And when city staffers would respond, Bernstein said, they asked for new requirements that weren’t previously mentioned. For example, he said he was asked to add walls inside the space in case future tenants of the building wanted to turn it into a church and too many people might crowd inside.

“They’ve made us put up dividing walls so that there couldn’t be that many people (in the space) for the next tenant as opposed to having an open floor plan like I want now,” he said. “We had to build unusable space.”

Bernstein started the application process around Thanksgiving and just got his construction permit from the city last month. He plans to open the new location in September.

“Honestly, it was a nightmare,” he said. “… This process makes it so prohibitive for anybody to start a business outside of people who already have enough money to pull it off, or somebody like me who has eight years of experience and has investors.”

Residential impacts, too

Bernstein’s story is not unique. Other local business owners have complained of similar issues. And in many cases, these business owners have been stuck paying rent on their commercial space while waiting for their use reviews to be approved by the city — a process that in recent years has taken an average of 200 days, or almost seven months.

Restaurants especially have been bogged down by bureaucracy. Restaurants are frequently subjected to use reviews and have restrictions on their square footage, patio size and hours of operation. Last year, City Council members expressed a desire to loosen some of these restrictions to make it easier for restaurants to do business in Boulder.

Josh Dinar went through the city’s use review process in 2015 and 2016, when he opened River and Woods at 2328 Pearl St. Dinar said it took almost a year to open the restaurant in a space that had already been a restaurant for four decades.

Like Bernstein, Dinar also found himself frequently waiting for responses from the city, and he also was asked to make changes during his the review process. Some of the city’s requests to Dinar included a parking reduction and installing bike parking outside the building that can withstand 150 mph winds.

“(It was like) something out of a satire for a while there, how long things could take,” Dinar said.

To the city’s credit, Dinar said, there were staffers who helped him navigate this process. But he said that while he loves Boulder and has lived here for a long time, he would not open another business in town.

The development review process also has impacts on the residential side, according to Bryan Bowen, an architect and former member of the city’s Planning Board. Bowen said the approval process for everything from large-scale housing developments to small improvements homeowners want to make can be onerous.

“The easiest thing to do in the city of Boulder is to build a very large house for a wealthy person. … Everything else is more difficult,” he said. “But if you asked the City Council what their highest priorities were for land use in the city, it probably isn’t just more wealthy person housing. It’s the middle-income housing, it’s duplexes (and) triplexes, the missing middle and affordable housing.”

Reduced review time

Boulder’s City Council unanimously voted last month to amend the city’s land use code and streamline the development review process. Although the council made numerous changes, some of the major ones included reducing the types of applications that require a call-up, or review, by the Planning Board. Call-ups are no longer required for floodplain and wetlands projects.

The call-up process adds time and administrative effort to the review process, and the city estimates that Planning Board call-ups could be reduced by about 40%. This change could also cut down the review time for applicants by two to four weeks.

Additionally, the council approved creating a new “minor use review” process that allows straightforward use reviews on nonresidential projects in nonresidential areas to also bypass the Planning Board call-up process if they don’t include any site changes. These types of reviews would also not need to go through the city’s development agreement process. The city estimates about 40% of use reviews in 2018-2023 could have been processed as minor use reviews, which would take less time to approve than a typical use review.

The changes have been celebrated by groups such as the Boulder Chamber and Better Boulder. Jonathan Singer, senior director of policy programs for the Boulder Chamber, spoke in support of the changes at a City Council meeting last month shortly before the changes were approved.

“The one key takeaway that I gave City Council was, this is amazing progress. Don’t stop now,” Singer told the Daily Camera. “These are tangible benefits that will improve every sector of our economy. And at the same time, we know, and city staff knows, that applications need to continue to move expeditiously to make sure that businesses can move forward with their goals.”

And for their part, Bernstein and Dinar both said they’re appreciative of the changes.

“The fact that they’re coming and saying, ‘We’re trying to make the process easier,’ and that they’ve stated that as a purpose — it’s great to hear,” Dinar said. “It’s highly appreciated that they’re thinking about how to do that and what can be made better.”

Said Bernstein, “I’m very, very happy to hear that they’re streamlining this, because it was an incredibly frustrating and tiring process.”

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David S. Chang, ChFC®, CLU® is an award-winning entrepreneur, keynote speaker, author, and consultant. He has over two decades of experience in the wealth management space and has been featured in dozens of news, radio, and podcast programs nationwide. He currently works as Head of IoT for the West Region of a Fortune 200 company. He is a graduate of the United States Military Academy at West Point and currently a Lieutenant Colonel in the California Army National Guard. He is an East-West Graduate Degree Fellow and has an MBA from the UCLA Anderson School of Management.

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Teenagers and young adults often find it difficult to manage their finances. Many financial institutions have now introduced specific financial tools and services for teenagers to help them learn money management skills. One such financial service is the Capital One MONEY Teen Checking Account, which is specifically designed for teenagers under the age of 18. We'll review the account in detail to see if a Capital One MONEY Teen Checking Account is right for you.

Capital One MONEY Teen Checking Account

• No monthly fees or balance requirements
• Strong mobile app
• Parent monitoring features
• Debit card for teens
• No out-of-network ATM fee reimbursements
• Can only open an account online
• Total card purchases and withdrawals are limited to $500 per day

Parents and teens have their own mobile app logins for the Capital One MONEY Teen Checking Account. Teens can manage their money, while parents have visibility and control, including the ability to lock the debit card. Capital One also has over 280 branches and over 50 Capital One Cafes, where account holders can bank, get a cup of coffee, and find advice from a certified money coach. In addition, the Capital One MONEY Teen Checking Account comes with no minimum deposit/balance requirements, no foreign transaction or overdraft fees, and early direct deposit availability.

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We recommend comparing checking accounts to make sure you're getting the best fit for you. Here's a list of our favorite accounts .

Full Capital One MONEY Teen Checking Account review

No monthly fees or balance requirements: The best student checking accounts have no fees. With the Capital One MONEY Teen Checking Account, there are no fees or minimums required. In addition there are no checking account fees for the debit card, for foreign transactions, or to transfer money from internal or external accounts. In addition, the APY offered by Capital One is slightly higher than the national average.

Strong mobile app: In 2022 Capital One's mobile all was ranked No 1 for both J.D. Power's 2022 U.S. Banking Mobile App Satisfaction Study and 2022 U.S. Online Banking Satisfaction Study. For 2023, Capital One dropped one ranking in the 2023 Banking Mobile App Satisfaction Study but still retained the top spot in the 2023 U.S. Online Banking Satisfaction Study.

Parent monitoring features: As a joint account holder, parents will be able to access their teen's checking account anytime with their own username and password. Parents can set up text alerts and email notifications for card transactions and account activity. Parents or legal guardians can send both automatic allowance and one-time money transfers, reward their teen's goals, withdraw money, view transactions, and receive text alerts and notifications through the Capital One Mobile app.

Debit card for teens with access to more than 70,000 ATMs: Teen account holders receive a Mastercard debit card in their name that they can use to make purchases or withdraw cash almost anywhere Mastercard is accepted. (Sweet!) They'll also be able to make free cash withdrawals at any Capital One or Allpoint® ATM.

What could be improved

No out-of-network ATM fee reimbursements: Capital One doesn't charge ATM fees at more than 70,000 fee-free ATMs nationwide. However, if you use another bank's ATM, you may be charged $2 or more. Capital One doesn't reimburse these fees.

Can only open an account online: The Capital One MONEY Teen Checking Account can only be opened online . Once opened, you can visit a Capital One branch and Cafe to manage your account.

Total card purchases and withdrawals are limited to $500 per day: If the account holder is less than 18 years old, the total card purchases and withdrawals are limited to $500 per day. This includes ATM withdrawals, cash advances, and signature and PIN-based purchases. This can be good or bad, depending on the circumstances. Parents or guardians can lower this limit further if they choose.

No checks: Capital One MONEY Teen Checking Account accounts are paper-free and don't offer checks. While you can deposit checks, you can't use checks to make a withdrawal from your Capital One MONEY Teen Checking Account.

How to access your money

It is simple to make deposits and withdrawals with your Capital One MONEY Teen Checking Account.

Deposit options

There are multiple ways to deposit funds, including:

• Automated Clearing House (ACH)
• Domestic wire transfer or other payment network transfers
• Transfer from another eligible Capital One, N.A. deposit account.

Withdrawal options

You can withdraw money using the following methods:

• Using the website or mobile app
• ATM withdrawals
• Visiting one of our branch locations
• Calling the bank

Capital One MONEY Teen Checking Accountis right for you if:

• You are a teen who wants a debit card and an interest-bearing account with no fees.
• You are a teen who wants a top-rated mobile app to help you make smarter money decisions.
• You are a parent who wants to stay on top of your child's spending and take advantage of teachable money moments.
• You are a parent who wants a top-rated app that makes it easy to auto-pay allowance, track account activities, and lock and unlock your kid's debit card if you need to.

Read more about Capital One

• Capital One Bank Review
• Capital One 360 Checking Review
• Capital One 360 Performance Savings Review
• Capital One Spark Business Basic Checking Review
• Capital One CD Rates

Our checking account methodology

At The Motley Fool Ascent, we rate checking accounts on a five-star scale (1 = poor, 5 = best). We evaluate all checking accounts across four main criteria: brand and reputation, APY and rewards, fees and minimum requirements, and perks.

Our scores are weighted as:

• Brand and reputation: 40%
• APY and rewards: 30%
• Fees and minimums: 15%
• Other perks: 15%

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Any child age 8 and up can be a joint account holder with their parent or legal guardian. To open an account, you and your teen will just need to provide details like your address, dates of birth, and Social Security numbers.

Once they turn 18, your teen can choose to open a 360 Checking account and transfer their balance from their MONEY account. (If they don't choose to open a 360 Checking checking account, the MONEY account remains open.)

No, MONEY accounts are only available online. You can still go to a branch or Capital One Cafe to help manage your money, however.

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• Title 10 —Energy
• Chapter III —Department of Energy
• Part 900 —Coordination of Federal Authorizations for Electric Transmission Facilities

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16 U.S.C. 824p(h) .

89 FR 35367 , May 1, 2024, unless otherwise noted.

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§ 900.8 IIP Process review meeting.

( a ) An Integrated Interagency Pre-Application (IIP) Process review meeting is required for each proposed electric transmission project utilizing the IIP Process and may only be held after the project proponent submits a review meeting request to DOE. The project proponent may submit the request at any time following submission of the initial resource reports required under § 900.6 . The review meeting request must include:

( 1 ) A summary table of changes made to the proposed project since the IIP Process initial meeting, including potential environmental and community benefits from improved siting or design;

( 2 ) Maps of potential routes and study corridors, including the proposed line, substations, and other infrastructure, as applicable, with at least as much detail as required for the initiation request described by § 900.5 and as modified in response to early stakeholder input and outreach and feedback from relevant Federal entities and relevant non-Federal entities;

( 3 ) If known, a schedule for completing any upcoming field resource surveys, as appropriate;

( 4 ) A conceptual plan for implementation and monitoring of proposed mitigation measures to avoid, minimize, or compensate for effects of the proposed project, consistent with 40 CFR 1508.1(s) or any successor regulation. This may include compensatory mitigation measures (offsite and onsite);

( 5 ) An updated public engagement plan described in § 900.5(d)(2) , reflecting actions undertaken since the project proponent submitted the initiation request and input received from relevant Federal entities and relevant non-Federal entities;

( 6 ) A listing of:

( i ) The dates on which the project proponent filed applications or requests for Federal authorizations and the dates on which the project proponent filed revisions to previously filed applications or requests; and

( ii ) Estimated dates for filing remaining applications or requests for Federal authorization;

( 7 ) Estimated dates that the project proponent will file requests for authorizations and consultations with relevant non-Federal entities; and

( 8 ) A proposed duration for each Federal land use authorization expected to be required for the proposed project, commensurate with the anticipated use of the proposed electric transmission facility.

( b ) Not later than 10 calendar days after the date that DOE receives the review meeting request, DOE shall provide relevant Federal entities and relevant non-Federal entities with materials included in the request and the initial resource reports submitted under § 900.6 via electronic means.

( c ) Not later than 60 calendar days after the date that DOE receives the review meeting request, DOE shall:

( 1 ) Determine whether the meeting request meets the requirements of paragraph (a) of this section and whether the initial resource reports are sufficiently detailed; and

( 2 ) Give notice to the project proponent and relevant Federal and non-Federal entities of DOE's determinations under paragraph (c)(1) of this section.

( d ) If DOE determines under paragraph (c)(1) of this section that the meeting request does not meet the requirements of paragraph (a) of this section or that the initial resource reports are not sufficiently detailed, DOE must provide the reasons for that finding and a description of how the project proponent may address any deficiencies in the meeting request or resource reports so that DOE may reconsider its determination.

( e ) Not later than 15 calendar days after the date that DOE provides notice to the project proponent under paragraph (c) of this section that the review meeting request and initial resource reports have been accepted, DOE shall convene the review meeting with the project proponent and the relevant Federal entities. All relevant non-Federal entities participating in the IIP Process shall also be invited.

( f ) During the IIP Process review meeting:

( 1 ) The relevant Federal entities shall discuss, and modify if needed, the analysis areas used in the initial resource reports;

( 2 ) Relevant Federal entities shall identify any remaining issues of concern, known information gaps or data needs, and potential issues or conflicts that could impact the time it will take the relevant Federal entities to process applications for Federal authorizations for the proposed electric transmission project;

( 3 ) Relevant non-Federal entities may identify remaining issues of concern, information needs, and potential issues or conflicts for the project;

( 4 ) The participants shall discuss the project proponent's updates to the siting process to date, including stakeholder outreach activities, resultant stakeholder input, and project proponent response to stakeholder input;

( 5 ) Led by DOE, all relevant Federal entities shall discuss statutory and regulatory standards that must be met to make decisions for Federal authorizations required for the proposed project;

( 6 ) Led by DOE, all relevant Federal entities shall describe the process for, and estimated time to complete, required Federal authorizations and, where possible, the anticipated cost ( e.g., processing and monitoring fees and land use fees);

( 7 ) Led by DOE, all relevant Federal entities shall describe their expectations for complete applications for Federal authorizations for the proposed project;

( 8 ) Led by DOE, all relevant Federal entities shall identify necessary updates to the initial resource reports that must be made before conclusion of the IIP Process, or, as necessary, following conclusion of the IIP Process; and

( 9 ) DOE shall present the proposed project-specific schedule developed under § 900.7 .

( g ) Not later than 10 calendar days after the review meeting, DOE shall:

( 1 ) Prepare a draft review meeting summary that includes a summary of the meeting discussion, a description of key issues and information gaps identified during the meeting, and any requests for more information from relevant Federal entities and relevant non-Federal entities; and

( 2 ) Convey the draft summary to the project proponent, relevant Federal entities, and any non-Federal entities that participated in the meeting.

( h ) The project proponent and entities that received the draft review meeting summary under paragraph (g) of this section will have 10 calendar days following receipt of the draft to review the draft and provide corrections to DOE.

( i ) Not later than 10 calendar days following the close of the 10-day review period under paragraph (h) of this section, DOE shall:

( 1 ) Prepare a final review meeting summary incorporating received corrections, as appropriate;

( 2 ) Add the final summary to the consolidated administrative docket described by § 900.10 ; and

( 3 ) Provide an electronic copy of the summary to the relevant Federal entities, relevant non-Federal entities, and the project proponent.

( j ) Not later than 10 calendar days following the close of the 10-day review period under paragraph (h) of this section, DOE shall:

( 1 ) determine whether the project proponent has developed the scope of its proposed project and alternatives sufficiently for DOE to determine that there exists an undertaking for purposes of section 106 of the NHPA; and

( 2 ) if the scope is sufficiently developed, initiate consultation with SHPOs, THPOs, and others consistent with 36 CFR 800.2(c)(4) , which may include authorizing a project proponent, as a CITAP applicant, to initiate section 106 consultation and providing appropriate notifications.

( k ) After the review meeting and before the IIP Process close-out meeting described by § 900.9 the project proponent shall revise resource reports submitted under § 900.6 based on feedback from relevant Federal entities and relevant non-Federal entities received during the review meeting and based on any updated surveys conducted since the initial meeting.

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Hitac: a hierarchical taxonomic classifier for fungal ITS sequences compatible with QIIME2

• Fábio M. Miranda 1 , 2 ,
• Vasco C. Azevedo 3 ,
• Rommel J. Ramos 3 , 4 , 5 ,
• Bernhard Y. Renard 1   na1 &
• Vitor C. Piro 1 , 2   na1  

BMC Bioinformatics volume  25 , Article number:  228 ( 2024 ) Cite this article

172 Accesses

1 Altmetric

Metrics details

Fungi play a key role in several important ecological functions, ranging from organic matter decomposition to symbiotic associations with plants. Moreover, fungi naturally inhabit the human body and can be beneficial when administered as probiotics. In mycology, the internal transcribed spacer (ITS) region was adopted as the universal marker for classifying fungi. Hence, an accurate and robust method for ITS classification is not only desired for the purpose of better diversity estimation, but it can also help us gain a deeper insight into the dynamics of environmental communities and ultimately comprehend whether the abundance of certain species correlate with health and disease. Although many methods have been proposed for taxonomic classification, to the best of our knowledge, none of them fully explore the taxonomic tree hierarchy when building their models. This in turn, leads to lower generalization power and higher risk of committing classification errors.

Here we introduce HiTaC, a robust hierarchical machine learning model for accurate ITS classification, which requires a small amount of data for training and can handle imbalanced datasets. HiTaC was thoroughly evaluated with the established TAXXI benchmark and could correctly classify fungal ITS sequences of varying lengths and a range of identity differences between the training and test data. HiTaC outperforms state-of-the-art methods when trained over noisy data, consistently achieving higher F1-score and sensitivity across different taxonomic ranks, improving sensitivity by 6.9 percentage points over top methods in the most noisy dataset available on TAXXI.

Conclusions

HiTaC is publicly available at the Python package index, BIOCONDA and Docker Hub. It is released under the new BSD license, allowing free use in academia and industry. Source code and documentation, which includes installation and usage instructions, are available at https://gitlab.com/dacs-hpi/hitac .

Peer Review reports

In the last decades, there has been a surge of interest in characterizing the mycoflora of communities. This is due to the fact that fungi are key organisms in several important ecological functions, ranging from nutrient recycling to mycorrhizal associations and decomposition of wood and litter [ 1 ]. Moreover, fungi naturally inhabit the human body and may benefit the host when administered as probiotics [ 2 ], yet little is known about the fungal microbiota of healthy individuals when compared to the bacterial microbiome [ 3 ]. Furthermore, identifying the presence of fungi can be challenging, as they rarely form structures visible to the naked eye, and similar structures are frequently composed of several distinct species [ 4 ]. Hence, it became common practice to use DNA sequencing in addition to morphological studies in contemporary mycology [ 5 ].

One of the approaches that can be employed in environmental studies is whole-genome shotgun sequencing (WGS), where the purpose is to obtain the genetic material of all organisms present in a given microbiome simultaneously [ 6 ]. Nonetheless, in studies where the end goal is only to estimate the diversity or discover the evolutionary distance of organisms in a microbiome, it is cheaper and more convenient to sequence only genetic markers such as 16 S rRNA, which is well conserved in all bacteria [ 7 ] and also widely used to classify and identify archaea [ 8 ]. In mycology, the internal transcribed spacer (ITS) region was adopted as the universal marker for classifying fungi [ 9 ].

The main characteristic of 16 S rRNA that makes it a good genetic marker is the presence of nine hypervariable regions V1–V9, which are flanked by conserved regions that can be used to amplify target sequences using universal primers [ 10 ]. However, 16 S rRNA has fewer hypervariable domains in fungi, and consequently, it is more appropriate to use the ITS region (Fig.  1 ), which is flanked by the 18 S and 28 S rRNA genes and interrupted by the conserved 5.8S rRNA gene [ 11 ]. Additionally, the ease with which ITS is amplified makes it an appealing target for sequencing samples from environments as challenging as soil and wood, where the initial quantity and quality of DNA is low [ 4 ].

Visual representation of the ITS region. The ITS region consists of the ITS1 and ITS2 regions, which are flanked by the 18 S and 28 S rRNA genes and separated by the conserved 5.8S rRNA gene [ 11 ]

From a computational perspective, the taxonomic classification of ITS fungal sequences can be performed by using either similarity-based or machine learning techniques. Similarity-based approaches, such as BLAST [ 12 ], require the alignment of a query sequence against all sequences available in a reference database, e.g., Silva [ 13 ] and UNITE [ 14 ]. However, a major limitation of similarity-based methods is the dependence on homologs in databases, which are not always available, while machine learning methods can learn only the relevant features and criteria for classification and can, therefore, be applied to any new sequence [ 15 ].

One of the first machine learning software proposed to perform taxonomic classification was the RDP-Classifier, which uses 8-mer frequencies to train a Naive Bayes classification algorithm [ 16 ]. Improving upon the RDP-Classifier, a novel Naive Bayes classifier with multinomial models was developed to increase the accuracy [ 17 ]. This multinomial classifier was later reimplemented and optimized on Microclass [ 18 ].

Other machine learning approaches have also been proposed in the literature, such as the k-Nearest Neighbor (KNN) algorithm [ 19 ]. Given a query sequence, the KNN algorithm identifies the k-most similar sequences in a database and uses the taxonomic information from each of those sequences to determine the consensus taxonomy. Q2_SK [ 20 ] implements several supervised learning classifiers from scikit-learn [ 21 ], e.g., Random Forest, Support Vector Machines (SVM) and Gradient Boosting. Q2_SK is flexible and allows the selection of features and classifiers.

Despite the advances made in taxonomic classification, there are still opportunities for enhancement due to the complexity of the data. Furthermore, to the best of our knowledge, the machine learning software available may lack in predictive performance since they perform flat classification, which means that they are only trained on leaf node labels and do not fully explore the hierarchical structure of the taxonomic tree when building their models (see Fig.  S1 for a depiction of the hierarchical structure of the taxonomic tree). The main disadvantage of this approach is that the information about parent–child class relationships in the hierarchical structure is not entirely considered, which may cause flat classifiers to commit more errors than hierarchical approaches [ 22 ]. Therefore, we developed a new hierarchical taxonomic classifier for fungal ITS sequences, denominated HiTaC, which explores the hierarchical structure of the taxonomic tree during the training stage and improves the F1-score and sensitivity of fungal ITS predictions. Furthermore, HiTaC can be easily installed and is compatible with QIIME2, facilitating its adoption in existing ITS sequence analysis pipelines.

Implementation

The local hierarchical taxonomic classifier.

HiTaC performs feature extraction, building of the hierarchical model, taxonomic classification, and reporting of the predictions. Figure  2 illustrates the algorithmic steps of HiTaC, where it starts by decomposing the DNA sequences from both reference and query files into their constituents k-mers. Next, two k-mer frequency matrices are built for the reference and query sequences, respectively, where each row contains the k-mer frequency for a sequence. Logistic regression classifiers implemented in the library scikit-learn [ 21 ] are trained for each parent node in the taxonomic hierarchy, using the local classifier per parent node implementation from a library called HiClass that we developed and published previously [ 23 ]. The k-mer frequency matrix and taxonomic labels of the reference sequences are used as training data to predict children labels (see Fig.  3 for a visual representation). The mycological nomenclature used as labels for the internal nodes originates from the taxonomy provided by the user, which allows the user to decide whether to use Index Fungorum [ 24 ], Faces of Fungi [ 25 ], Mycobank [ 26 ], or The NCBI taxonomy database [ 27 ], for example. Predictions are performed using the k-mer frequency matrix computed for the query sequences and are reported in a top-down approach, based on the taxonomic hierarchy. For example, if the classifier at the root node predicts that a query sequence belongs to the phylum Ascomycota, then only that branch of the taxonomic tree will be considered for the remaining taxonomic levels.

Sketch of the key algorithmic components of HiTaC

HiTaC algorithm overview. To compute the k-mer frequency of DNA sequences, we first decompose them into their constituent k-mers. In the example shown in step 01, \(k=3\) , resulting in 5 sub-strings. Afterwards, HiTaC computes a matrix containing the k-mer frequency for all training sequences, where each row contains the k-mer frequency for a given sequence and the columns are all possible k-mers for a given k , i.e., all k nucleotide permutations of A, C, G and T. Next, HiTaC trains a logistic regression classifier for each parent node in the taxonomic tree, where the features are the k-mer frequencies computed in step 2 and the labels are the taxonomic annotations of the training sequences. In step 03, only the first 2 levels are shown for brevity. Lastly, HiTaC makes predictions in a top-down approach, based on the taxonomic hierarchy

Classification uncertainty

To reduce classification errors when faced with uncertainties, we also construct a filter by training a logistic regression classifier for each level of the hierarchy. This filter computes confidence scores for all taxonomic ranks assigned by the local classifier per parent node and excludes labels that are below a user-defined threshold in a bottom-up approach (Fig.  4 ). The confidence scores are computed using the predict_proba method implemented in scikit-learn’s logistic regression classifier, which in turn uses a one-vs-rest approach; that is, it calculates the probability of each class using the logistic function and assuming it to be positive, then it normalizes these values across all the classes [ 28 ].

HiTaC filter overview. To build the filter, we first train a logistic regression classifier for each level of the hierarchy, using the same k-mer frequency algorithm introduced previously on Fig.  3 . In the example shown in step 01, there are only 3 levels in the hierarchy for simplicity. Afterwards, HiTaC computes the confidence score for all taxonomic ranks assigned to a sample by the local classifier per parent node, then on a bottom-up approach it removes labels that are below a certain threshold. In step 02, supposing that the threshold is 0.7 and that the given sample has a confidence score of 0.2 assigned for the lowest rank, then the final prediction for this sample will only contain the labels Fungi and Ascomycota

Code quality assurance

The code base adheres to the PEP 8 code style [ 29 ], which is enforced by flake8 and the uncompromising code formatter black to ensure high code quality. Versioning complies with SemVer to increase reproducibility and facilitate dependency management by end users. The code is accompanied by unit tests that cover 98% of the code base and are automatically executed by our continuous integration workflow upon commits.

Installation and usage

HiTaC is hosted on GitLab Footnote 1 , where there is also documentation with installation and usage instructions. HiTaC is compatible with Python 3.8+ and can be installed on GNU/Linux, Windows and macOS. It can be easily obtained with pip install hitac , conda install -c bioconda hitac or docker pull mirand863/hitac . Listing 1 shows a basic example of how to fit a hierarchical model and predict the taxonomy using HiTaC. More elaborate examples can be found in the documentation.

Listing 1 Example of how to use HiTaC to train a hierarchical classifier and predict taxonomy

We evaluated HiTaC in five datasets with varying sequence lengths (Tables S2 – S3 ) and compared its performance against seventeen taxonomic classifiers using the TAXXI benchmark [ 30 ]. All methods evaluated were trained and tested with the same data in order to avoid bias. The commands and parameters executed are summarized in Tables S4 – S22 .

To measure the performance of our model, we adopted all metrics available in the TAXXI benchmark and extended them by adding standard machine learning metrics. Furthermore, we also computed hierarchical metrics, which can give better insights into which algorithm is better at classifying hierarchical data [ 22 ]. The definitions of all these metrics are listed in the supporting information text.

The datasets in the TAXXI benchmark were created using real environmental data, publicly available on NCBI [ 31 ], RDP [ 32 ], the Warcup fungal ITS training set v2 (WITS) [ 33 ], UNITE [ 34 ] and other in vivo samples [ 30 ]. These datasets were created with a strategy known as cross-validation by identity, where varying distances between query sequences and the reference database are accounted for. In practice, this means that in the dataset with 90% identity all species are novel and there is a mix of novel and known taxa at the genus level, making it the most difficult dataset in the benchmark. As the identity increases, so does the amount of known labels at all taxonomic ranks; hence, the dataset with 100% identity can be considered the easiest in the benchmark.

Results and discussion

First, we evaluated HiTaC on the dataset with 90% identity to assess its behavior under uncertainty. In order to do this, we computed the hierarchical precision to measure the proportion of correct predictions, the hierarchical recall to measure the proportion of detected positive samples and the hierarchical F1-score, which is the harmonic mean of the precision and recall. As shown in Fig.  5 , HiTaC_Filter was one of the top-performing methods in terms of precision, scoring 96.05 while maintaining a recall of 78.86, equivalent to other high-ranking methods. Although other software obtained similar or slightly better precision, it cost them a steeper decline in recall, which is also evidenced by the lower F1 scores. This result shows that HiTaC performed well in the presence of uncertainty.

Hierarchical f1-score, precision and recall computed for all taxonomic ranks for the dataset with 90% identity, sorted by f1-score. HiTaC_Filter was one of the best-performing methods when dealing with uncertainty, achieving high f1-score, precision and recall, while the filter-less version obtained the highest recall of all methods

To appraise HiTaC’s behavior when classifying known organisms, we evaluated it on the dataset with 100% identity. As shown in Fig.  6 , HiTaC_Filter achieved a perfect precision score of 100 when the taxonomy was fully annotated in the reference database. Furthermore, the recall persisted at 99.68; that is, there was no prominent decrease in recall when compared with the filter-less version. This result shows the potential of HiTaC in accurately classifying known organisms, given that query sequences have perfect matches in the reference database.

Hierarchical f1-score, precision and recall computed for all taxonomic ranks for the dataset with 100% identity. Both HiTaC and HiTaC_Filter achieved almost perfect scores when all organisms were known

Hierarchical F1-score computed for all taxonomic ranks for the datasets with 90, 95, 97, 99 and 100% identity, sorted by average. HiTaC_Filter achieved F1-scores equal to or above the best methods available in the literature

In Fig.  7 , we summarize the results achieved for the hierarchical metrics by computing the F1-score for all five datasets and sorting by the average of F1 scores. HiTaC_Filter obtained an F1-score equivalent or higher to the top-performing approaches for all datasets, corroborating the results presented in the previous paragraphs. This result demonstrates that HiTaC_Filter can positively identify organisms annotated in databases while being able to leave most new species unannotated.

Similar conclusions can be drawn from Fig.  8 , in which we evaluated the percentage of known sequences correctly predicted, i.e., the true positive rate (TPR) for all methods and datasets available in the benchmark. The trend is that HiTaC achieved a TPR higher or equal to top methods. For instance, the best true positive rate at the genus level for the dataset with 90% identity was achieved by HiTaC, which sharply increased the TPR by 6.9 percentage points when compared with BTOP. Regarding the dataset with 95% identity at the genus level, HiTaC obtained a 1.7 percentage points improvement over Microclass, while for the dataset with 97% identity at the genus level, HiTaC surpassed Microclass with a 0.5 increase in percentage points. At the species level, HiTaC achieved a 0.7 percentage points gain over BTOP for the dataset with 99% identity, while for the dataset with 100% identity, HiTaC tied with BTOP, obtaining a perfect score of 100% TPR. These results suggest that the local hierarchical classification approach implemented in HiTaC commits fewer errors than flat classifiers as long as the sequences are previously known.

True positive rates for all methods for the datasets with 90%, 95% and 97% identity at the genus level, and 99% and 100% identity at the species level. The trend is that HiTaC achieved a sensitivity higher or equal to top methods. For instance, HiTaC tied with the best method for the dataset with 100% identity, obtaining a perfect score. Moreover, for the datasets with 90–99% identity, HiTaC improved the true positive rates upon top methods

By default, HiTaC uses 6-mer frequency as a feature extraction method, but the user can change this parameter. Nevertheless, increasing the k-mer size provides small gains in predictive performance and comes with higher computational costs. The k-mer frequency computation method discards substrings with ambiguous nucleotides since they do not often occur in short reads, and accounting for them would require a slower algorithm. For example, a V means that there is either an A, C, or G in that position, and computing all these possibilities would make the method slower. Hence, we opted to disregard ambiguous nucleotides to keep the k-mer counting process as fast as possible. In future releases, we intend to implement a flexible user interface to allow users to use third-party feature extraction methods. Furthermore, we believe allowing for third-party feature extraction methods could also enable accurate taxonomic classification for 16 S rRNA.

Training the filter is slower than most methods evaluated in the benchmark (Tables S23 – S27 ). However, it must only be performed once for the reference database, and after training, the filter can be used to estimate the uncertainty quickly. Moreover, some public databases, such as UNITE and SILVA, are not updated frequently. Nevertheless, we provide models pre-trained on the public database UNITE Footnote 2 , speeding up the process for users. Some of these pre-trained models contain all eukaryotic ITS sequences available on UNITE, which enable detection and removal of nonfungal sequences mistakenly amplified by polymerase chain reaction (PCR) [ 35 ]. At the time of writing, the current version of UNITE uses the mycological nomenclature published in Fungal Diversity [ 36 ]; hence, this is the nomenclature HiTaC learns when trained with the UNITE database and is reported to the user with the pre-trained models. Furthermore, HiTaC uses the unique species hypotheses identifiers provided in the database UNITE as the last taxonomic level in the hierarchy during training and reports them to the user, which increases taxonomic reproducibility.

On average, the entire ITS region is approximately 600 base pairs (bp) in length [ 37 ]. This trend can also be observed in the UNITE database, with averages ranging from 578 bp to 651 bp. However, in the UNITE database, the sequence lengths can vary from 250 bp to 16,761 bp, while the ITS sequences in the TAXXI benchmark have a maximum length of 1373 bp.

In summary, HiTaC is a Python package optimized to produce accurate taxonomic classification of fungal ITS sequences. Due to the extensive use of the taxonomic hierarchy during training, HiTaC produces fewer errors than other methods compared in the benchmark. Furthermore, its filter is a reliable classifier under uncertainty. HiTaC provides standalone Python scripts and a QIIME 2 plugin that can be quickly adopted into existing analysis pipelines. HiTaC and its dependencies can be easily installed via pip , conda or docker , which is not the case for most of the taxonomic classifiers available in the literature. HiTaC is released under the new BSD license, allowing free use in academia and industry and free copy, modification, and redistribution of the code as long as a duplicate of the original license is kept and proper acknowledgments are given.

HiTaC is a Python package for the taxonomic classification of fungal ITS sequences, which applies local hierarchical classifiers for accurate predictions. It provides scripts to train classifiers on specialized datasets and to classify new sequences with the trained models. The standard version has high sensitivity and is ideal for exploratory analysis. HiTaC also implements a filter that can express uncertainties in classifications, indicating if the input sequences are complex to recognize. Thanks to its compatibility with QIIME 2, users can quickly adopt it in existing mycobiome analysis pipelines. HiTaC is an open-source software available at https://gitlab.com/dacs-hpi/hitac .

Availability of data materials

HiTaC is freely available on the Python package index, BIOCONDA and docker hub. It is easier to install it by executing pip install hitac in the terminal. All datasets and evaluation scripts used in this paper are publicly available in the TAXXI benchmark [ 30 ], and a reproducible evaluation pipeline is available on GitLab https://gitlab.com/dacs-hpi/hitac/-/tree/main/benchmark .

https://gitlab.com/dacs-hpi/hitac .

https://gitlab.com/dacs-hpi/hitac#pre-trained-models

Hawksworth DL. The magnitude of fungal diversity: the 1.5 million species estimate revisited. Mycol Res. 2001;105(12):1422–32.

Article   Google Scholar  

Banik A, Halder SK, Ghosh C, Mondal KC. Fungal probiotics: opportunity, challenge, and prospects. In: Recent advancement in white biotechnology through fungi: volume 2: perspective for value-added products and environments; 2019. pp. 101–117.

Huffnagle GB, Noverr MC. The emerging world of the fungal microbiome. Trends Microbiol. 2013;21(7):334–41.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Nilsson RH, Ryberg M, Abarenkov K, Sjökvist E, Kristiansson E. The its region as a target for characterization of fungal communities using emerging sequencing technologies. FEMS Microbiol Lett. 2009;296(1):97–101.

Article   CAS   PubMed   Google Scholar  

Hibbett DS. After the gold rush, or before the flood? Evolutionary morphology of mushroom-forming fungi (agaricomycetes) in the early 21st century. Mycol Res. 2007;111(9):1001–18.

Article   PubMed   Google Scholar  

Venter JC, Remington K, Heidelberg JF, Halpern AL, Rusch D, Eisen JA, Wu D, Paulsen I, Nelson KE, Nelson W. Environmental genome shotgun sequencing of the Sargasso sea. Science. 2004;304(5667):66–74.

Fuhrman JA. Metagenomics and its connection to microbial community organization. F1000 Biol Rep. 2012;4:12.

Kim M, Chun J. 16s rrna gene-based identification of bacteria and archaea using the eztaxon server. In: Methods in microbiology, vol 41; Elsevier. pp. 61–74.

Schoch, C.L., Seifert, K.A., Huhndorf, S., Robert, V., Spouge, J.L., Levesque, C.A., Chen, W., Consortium, F.B.,. Nuclear ribosomal internal transcribed spacer (its) region as a universal dna barcode marker for fungi. Proc Natl Acad Sci. 2012;109(16):6241–6.

Chakravorty S, Helb D, Burday M, Connell N, Alland D. A detailed analysis of 16s ribosomal rna gene segments for the diagnosis of pathogenic bacteria. J Microbiol Methods. 2007;69(2):330–9.

Dos Reis JBA, Lorenzi AS, Vale HMM. Methods used for the study of endophytic fungi: a review on methodologies and challenges, and associated tips. Arch Microbiol. 2022;204(11):675.

Article   PubMed   PubMed Central   Google Scholar  

Altschul SF, Madden TL, Schäffer AA, Zhang J, Zhang Z, Miller W, Lipman DJ. Gapped blast and psi-blast: a new generation of protein database search programs. Nucleic Acids Res. 1997;25(17):3389–402.

Pruesse E, Quast C, Knittel K, Fuchs BM, Ludwig W, Peplies J, Glöckner FO. Silva: a comprehensive online resource for quality checked and aligned ribosomal rna sequence data compatible with arb. Nucleic Acids Res. 2007;35(21):7188–96.

Nilsson RH, Larsson K-H, Taylor AFS, Bengtsson-Palme J, Jeppesen TS, Schigel D, Kennedy P, Picard K, Glöckner FO, Tedersoo L. The unite database for molecular identification of fungi: handling dark taxa and parallel taxonomic classifications. Nucleic Acids Res. 2018;47(D1):259–64.

Bzhalava Z, Tampuu A, Bała P, Vicente R, Dillner J. Machine learning for detection of viral sequences in human metagenomic datasets. BMC Bioinform. 2018;19:1–11.

Wang Q, Garrity GM, Tiedje JM, Cole JR. Naive bayesian classifier for rapid assignment of rrna sequences into the new bacterial taxonomy. Appl Environ Microbiol. 2007;73(16):5261–7.

Liu K-L, Wong T-T. Naïve bayesian classifiers with multinomial models for rrna taxonomic assignment. IEEE/ACM Trans Comput Biol Bioinf. 2013;10(5):1–1.

Liland KH, Vinje H, Snipen L. microclass: an r-package for 16s taxonomy classification. BMC Bioinform. 2017;18(1):172.

Schloss PD, Westcott SL, Ryabin T, Hall JR, Hartmann M, Hollister EB, Lesniewski RA, Oakley BB, Parks DH, Robinson CJ. Introducing mothur: open-source, platform-independent, community-supported software for describing and comparing microbial communities. Appl Environ Microbiol. 2009;75(23):7537–41.

Bokulich NA, Dillon MR, Bolyen E, Kaehler BD, Huttley GA, Caporaso JG. q2-sample-classifier: machine-learning tools for microbiome classification and regression. J Open Res Softw. 2018;3:30.

Google Scholar  

Pedregosa F, Varoquaux G, Gramfort A, Michel V, Thirion B, Grisel O, Blondel M, Prettenhofer P, Weiss R, Dubourg V. Scikit-learn: machine learning in python. J Mach Learn Res. 2011;12:2825–30.

Silla CN, Freitas AA. A survey of hierarchical classification across different application domains. Data Min Knowl Disc. 2011;22(1–2):31–72.

Miranda FM, Köhnecke N, Renard BY. Hiclass: a python library for local hierarchical classification compatible with scikit-learn. J Mach Learn Res. 2023;24(29):1–17.

Index Fungorum. https://www.indexfungorum.org/ . Accessed 13 May 2024.

Jayasiri SC, Hyde KD, Ariyawansa HA, Bhat J, Buyck B, Cai L, Dai Y-C, Abd-Elsalam KA, Ertz D, Hidayat I. The faces of fungi database: fungal names linked with morphology, phylogeny and human impacts. Fungal Divers. 2015;74:3–18.

Robert V, Vu D, Amor ABH, Wiele N, Brouwer C, Jabas B, Szoke S, Dridi A, Triki M, Daoud SB. Mycobank gearing up for new horizons. IMA Fungus. 2013;4:371–9.

Federhen S. The ncbi taxonomy database. Nucleic Acids Res. 2012;40(D1):136–43.

Scikit-learn: logistic regression probability estimates. 2023. https://scikit-learn.org/stable/modules/generated/sklearn.linear_model.LogisticRegression.html . Accessed 26 Oct 2023.

Rossum G, Warsaw B, Coghlan N. PEP 8-style guide for Python code. python.org 2001.

Edgar RC. Accuracy of taxonomy prediction for 16s rrna and fungal its sequences. PeerJ. 2018;6:4652.

Sayers EW, Barrett T, Benson DA, Bolton E, Bryant SH, Canese K, Chetvernin V, Church DM, DiCuccio M, Federhen S. Database resources of the national center for biotechnology information. Nucleic Acids Res. 2012;40(D1):13–25.

Cole JR, Wang Q, Fish JA, Chai B, McGarrell DM, Sun Y, Brown CT, Porras-Alfaro A, Kuske CR, Tiedje JM. Ribosomal database project: data and tools for high throughput rrna analysis. Nucleic Acids Res. 2014;42(D1):633–42.

Deshpande V, Wang Q, Greenfield P, Charleston M, Porras-Alfaro A, Kuske CR, Cole JR, Midgley DJ, Tran-Dinh N. Fungal identification using a bayesian classifier and the warcup training set of internal transcribed spacer sequences. Mycologia. 2016;108(1):1–5.

Kõljalg U, Larsson K-H, Abarenkov K, Nilsson RH, Alexander IJ, Eberhardt U, Erland S, Høiland K, Kjøller R, Larsson E. Unite: a database providing web-based methods for the molecular identification of ectomycorrhizal fungi. New Phytol. 2005;166(3):1063–8.

Rawson C, Zahn G. Inclusion of database outgroups reduces false positives in fungal metabarcoding taxonomic assignments. Mycologia. 2023;8:1–7.

Tedersoo L, Sánchez-Ramírez S, Koljalg U, Bahram M, Döring M, Schigel D, May T, Ryberg M, Abarenkov K. High-level classification of the fungi and a tool for evolutionary ecological analyses. Fungal Divers. 2018;90:135–59.

Porras-Alfaro A, Liu K-L, Kuske CR, Xie G. From genus to phylum: large-subunit and internal transcribed spacer rrna operon regions show similar classification accuracies influenced by database composition. Appl Environ Microbiol. 2014;80(3):829–40. https://doi.org/10.1128/AEM.02894-13 .

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Acknowledgements

FMM gratefully acknowledges Marcos Augusto dos Santos (UFMG) for initial inspiration, Robert C. Edgar (independent researcher) for providing the scripts and datasets in the TAXXI benchmark, Sven Giese (HPI) for code improvement suggestions and Elizabeth Yuu (HPI) for proofreading.

Open Access funding enabled and organized by Projekt DEAL. VCP was financed by the Deutsche Forschungsgemeinschaft (DFG) under grant number 458163427.

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Bernhard Y. Renard and Vitor C. Piro shared senior co-authorship.

Authors and Affiliations

Data Analytics and Computational Statistics, Hasso Plattner Institute, Digital Engineering Faculty, University of Potsdam, Potsdam, Germany

Fábio M. Miranda, Bernhard Y. Renard & Vitor C. Piro

Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany

Fábio M. Miranda & Vitor C. Piro

Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil

Vasco C. Azevedo & Rommel J. Ramos

Institute of Biological Sciences, Federal University of Pará, Belém, Brazil

Rommel J. Ramos

Centro de Computação de Alto Desempenho, Universidade Federal do Pará, Belém, Brazil

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FMM designed and implemented HiTaC’s algorithm, performed analysis, benchmarked the experiments and wrote the manuscript. VAA and RJR assisted with analysis and revised the manuscript. BYR assisted with analysis, visualizations and reviewed the manuscript. VCP oversaw experimental and analysis aspects of the project and reviewed the manuscript. All authors edited and approved the final manuscript.

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Correspondence to Vitor C. Piro .

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Miranda, F.M., Azevedo, V.C., Ramos, R.J. et al. Hitac: a hierarchical taxonomic classifier for fungal ITS sequences compatible with QIIME2. BMC Bioinformatics 25 , 228 (2024). https://doi.org/10.1186/s12859-024-05839-x

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DOI : https://doi.org/10.1186/s12859-024-05839-x

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