Step by Step Guide to a Code Review


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Praise Iwuh

March 05, 2024

As we tilt more and more towards a society where everything runs on software and technology, from healthcare to finance and government infrastructure, it becomes necessary that the code powering this tech remains flawless. In seeking ways to maintain this, we identified code reviews as a critical way to ensure clean code.

In simple terms, a code review is a systematic examination of code changes performed by one or more developers to ensure its quality, correctness, and adherence to best practices. It is a crucial process in software development that involves systematically examining someone else's code to find errors, improve code quality, and share knowledge among team members. It plays a significant role in maintaining code reliability, catching bugs early, fostering collaboration, and ultimately delivering better software products.

In this step-by-step guide, we will delve deeper into what code reviews are and why they are essential in the software development lifecycle and walk through the process of conducting a thorough and effective code review.

  • What is a code review?
  • Why is a code review important?
  • Step-by-step guide to a code review
  • The code review process
  • Code review tools
  • Conclusion

What is a Code review?

At its core, a code review involves having one or more developers inspect another developer's code changes before they are integrated into the main codebase. This process can take various forms, including peer reviews, pull request reviews, or formal code inspections, depending on the team's preferences and the development workflow in place.

When trying to understand code reviews, think writer, editor, or chef and food critic. A writer completes their draft, which is inspected through and through by an editor to detect errors, improve structure, language, and whatever other guidelines they are to work under before publishing. The same can be said for a chef whose food and cooking process are subjected to careful but positive scrutiny by a critic before the dish is cleared for serving.

During a code review, the reviewer(s) examine the code changes line by line, looking for issues such as bugs, logic errors, performance bottlenecks, security vulnerabilities, and adherence to coding standards. Additionally, they assess the code's overall design, readability, and maintainability to ensure it meets the project's requirements and aligns with established best practices.

Why is Code Review Important?

Code reviews offer several benefits that contribute to the overall success of a software project:

Bug Detection: By having multiple sets of eyes inspecting the code changes, potential bugs and issues can be identified early in the development process, reducing the likelihood of costly defects slipping into production.

Knowledge Sharing: Code reviews provide an opportunity for team members to learn from each other by sharing insights, best practices, and alternative solutions. It fosters a culture of collaboration and continuous learning within the team.

Code Quality Improvement: Through constructive feedback and suggestions for improvement, code reviews help maintain and improve the overall quality of the codebase. This leads to cleaner, more maintainable code that is easier to understand and extend.

Consistency and Standards: Code reviews ensure consistency in coding style, documentation, and architectural decisions across the project. By enforcing coding standards and best practices, code reviews help prevent codebase fragmentation and ensure a higher level of maintainability over time.

Risk Mitigation: By thoroughly reviewing code changes before they are merged, code reviews help mitigate the risk of introducing regressions or breaking existing functionality. This is especially important in mission-critical systems or projects with strict quality and security requirements.

code review

Steps to a Code Review Process

There a certain code review checklists that guide developers when studying someone’s work. Following these steps ensure a thorough code review process.

Step 1: Understand the Purpose

Before diving into the code review process, it's essential to understand its purpose. Code reviews serve several purposes, including identifying defects, ensuring adherence to coding standards, sharing knowledge, and improving overall code quality. By understanding these objectives, reviewers can approach the review process with the right mindset and focus on delivering meaningful feedback.

Step 2: Choose the Right Tools

Selecting the appropriate tools for code review is crucial for streamlining the process and ensuring effectiveness. Many version control systems, such as Git, offer built-in features for code review, including pull requests and code review tools like GitHub, GitLab, and Bitbucket. These tools provide a platform for reviewing code changes, discussing issues, and tracking feedback. Additionally, there are standalone code review tools like Review Board and Gerrit that offer advanced features for code inspection and collaboration.

Step 3: Establish Review Guidelines

Establishing clear guidelines and standards for code reviews is essential for maintaining consistency and effectiveness across the team. These guidelines should cover aspects such as coding style, documentation requirements, testing practices, and expectations for review participation. By setting clear expectations, reviewers can provide constructive feedback that aligns with the project's goals and standards.

Step 4: Review Code Changes

When reviewing code changes, start by understanding the context and objectives of the proposed changes. This involves reading through the accompanying documentation, user stories, or bug reports to gain insights into the rationale behind the code modifications. Next, carefully examine the code changes line by line, paying attention to logic errors, potential bugs, code readability, performance issues, and adherence to coding standards.

Step 5: Provide Constructive Feedback

Effective code reviews involve providing constructive feedback that helps the author improve their code while maintaining a positive and collaborative atmosphere. When providing feedback, focus on specific issues rather than criticizing the author personally. Use a respectful tone and provide actionable suggestions for improvement, such as refactoring code, adding comments, or addressing edge cases. Additionally, praise the author for well-written code and commendable practices to reinforce positive behavior.

Step 6: Engage in Discussions

Code reviews are not just about pointing out flaws; they also provide an opportunity for collaboration and knowledge sharing. Engage in discussions with the author and other reviewers to clarify doubts, exchange ideas, and explore alternative solutions. Encourage open communication and constructive dialogue to foster a culture of continuous improvement within the team. Be receptive to feedback from others and willing to reconsider your opinions based on valid arguments presented during discussions.

Step 7: Follow Up on Feedback

After providing feedback on code changes, follow up on the suggested improvements to ensure they are addressed appropriately. Review the revised code to verify that the issues identified during the initial review have been resolved satisfactorily. If necessary, provide additional guidance or clarification to help the author implement the suggested changes effectively. By following up on feedback, you demonstrate your commitment to code quality and help maintain the integrity of the codebase.

Step 8: Document Decisions and Learnings

Documenting the decisions made during code reviews and capturing key learnings is essential for future reference and continuous improvement. Keep track of the issues identified, the rationale behind decisions, and any lessons learned during the review process. This documentation serves as a valuable resource for onboarding new team members, revisiting past decisions, and refining the code review process over time. Additionally, share insights and best practices with the team to promote a culture of learning and knowledge sharing.

Step 9: Reflect and Iterate

After completing a code review, take some time to reflect on the process and identify areas for improvement. Consider factors such as review efficiency, effectiveness of feedback, and overall satisfaction with the outcomes. Solicit feedback from team members to gather different perspectives and insights on how to enhance the code review process further. Use this feedback to iterate on your review practices continually and strive for continuous improvement.

The Code Review Process

 Let's delve into the essential steps of an effective code review:


Before diving into the review, it's crucial to set the stage. This involves establishing clear guidelines, defining the objectives of the review, and ensuring that the code is ready for evaluation. Developers should be familiar with the project requirements and coding standards to streamline the process.

Initial Code Submission

The process begins with the developer submitting their code for review. This step marks the transition of ownership from individual contributors to the collective team, where the code undergoes scrutiny and improvement.

Peer Review

Peer review forms the core of the code review process. Developers collaboratively examine the code, focusing on various aspects such as functionality, readability, maintainability, and adherence to coding standards. It's a collaborative effort aimed at uncovering issues and sharing insights to enhance the codebase.

Feedback and Comments

During the review, reviewers provide constructive feedback and comments on the code. This feedback should be specific, actionable, and respectful, aimed at guiding improvements rather than criticizing the developer. Clear communication is key to ensuring that feedback is understood and addressed effectively.


Based on the feedback received, the developer revises the code, addressing issues, incorporating suggestions, and making necessary improvements. This iterative process of revision and refinement is essential for enhancing code quality and fostering continuous improvement.

Final Approval

Once the necessary revisions are made, the code undergoes a final review to ensure that all issues have been addressed satisfactorily. Upon approval, the code is merged into the main codebase, ready for deployment.

Code Review Tools

Choosing the right code review tool depends on your specific needs and preferences. Here are some of the most popular options to consider:


A popular Git repository hosting service that also offers built-in code review functionalities. It allows for threaded discussions, code commenting, and integration with various continuous integration/continuous delivery (CI/CD) tools.


Another Git repository hosting service with integrated code review features. GitLab offers a comprehensive set of functionalities, including code review, issue tracking, project management, and CI/CD pipelines.


Bitbucket is a Git repository hosting service owned by Atlassian. It integrates well with other Atlassian products, like Jira, making it a good choice for teams already using that ecosystem.

Azure DevOps

Azure DevOps is a Microsoft suite of DevOps tools, including integrated code review functionalities. It is a good option for teams already invested in the Microsoft ecosystem.


Crucible is a standalone code review tool from Atlassian that can be integrated with various source code repositories. It offers a user-friendly interface and features like code commenting, highlighting, and threaded discussions.


An open-source code review tool that offers a wide range of features, including code review, issue tracking, and project management. Phabricator can be self-hosted or used as a hosted service.


SonarQube is a static code analysis tool that also offers code review functionalities. It can identify potential bugs, code smells, and security vulnerabilities.


Another static code analysis tool with code review capabilities. Codacy integrates with various platforms like GitHub, GitLab, and Bitbucket.

Review Board

Review Board is a free and open-source code review tool that can be integrated with various source code repositories. It offers a simple and lightweight interface for code review.


Veracode is a suite of application security testing (AST) tools that includes code review functionalities. It can identify security vulnerabilities in code and help developers remediate them.

These are just a few of the many code review tools available. The best tool for you will depend on your specific needs and preferences. When making your decision, consider factors such as the features you need, your budget, and your existing development workflow.


Code review is a critical practice that plays a vital role in ensuring the quality and maintainability of software projects. By following the step-by-step guide outlined above, teams can conduct thorough and effective code reviews that lead to improved code quality, reduced defects, and enhanced collaboration. Remember to approach code reviews with a constructive mindset, focus on providing actionable feedback, and embrace opportunities for learning and growth. By making code review a regular part of your development workflow, you can elevate the quality of your codebase and deliver better software products.

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