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6 Best Practices to Become a Better Code Reviewer

Last updated on: 
September 6, 2023
Dipen Dadhaniya
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About The Author!
Dipen Dadhaniya
Dipen Dadhaniya
Engineering Manager at Interview Kickstart. A passionate and versatile web developer packed with full-stack development skills and a curiosity to explore computer languages.

There are many reasons why you should learn code review best practices — code reviewers are crucial to the success of software projects. They examine each line of code (LOC)  to make sure that bugs and errors are eliminated. Complex software programs generally have innumerable lines of code, making it difficult for developers to take complete ownership to fix bugs and errors. As a code reviewer, following the universal code review best practices leads to better code reviews, paving the way for higher success of code executions.  

The benefits of doing code reviews in line with code review best practices are plenty. As a code reviewer, you get to spot review the work of developers and fix errors if there are any. You also learn from code snippets to find out the most optimal approaches and collaborate with innovative minds to understand the coding and algorithmic approaches for software programs, leading to better code reviews in the future. 

Code reviewers also employ tools that help review code better. These tools are sometimes sourced or built in-house. To excel at code reviews and avoid steering away from code review best practices, it is important to adopt a good strategy to fix erroneous lines of code and ensure that software programs run smoothly in accordance with the project’s goals. 

If you’re a software engineer, coding engineer, software developer, engineering manager, or tech lead preparing for tech interviews, check out our technical interview checklist, interview questions page, and salary negotiation e-book to get interview-ready! 

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In this article, we’ll look at some notable tips to become a high-quality code reviewer. You’ll understand how to review code better by following some noteworthy code review best practices. Here’s what we’ll discuss:

Responsibilities of Code Reviewers

Before we move on to understanding the code review best practices, let us first look at the responsibilities of code reviewers. Code reviewers are expected to be extremely good in the programming language that’s being used. They ensure the overall quality of the source code and fix a whole range of issues relating to the source code by conducting periodic reviews.

Code reviewers are expected to:

  • Conduct regular reviews of the source code
  • Ensure that the quality of the source code is maintained
  • Share knowledge of where code improvements can be undertaken
  • Provide periodic feedback to developers to enhance the quality of code
  • Detect bugs and errors in the code and fix them 

6 Tips on How to Review Code Better

If you want to know how to review code better, following effective code review techniques is extremely important. Below are some code review best practices that lead to better code reviews and consequently drive the success of software projects.

1. Make Sure That a Good Process and Tool Are in Place

Having a solid process in place is one of the most crucial code review best practices. Code reviews can be rendered ineffective if there’s no proper record of bugs that have been found and fixed. That’s why using a good code review tool is one of the most effective code review techniques. If there are multiple reviewers reviewing several lines of code every hour, using a collaborative tool where reviewers can log bug fixes is more of a necessity. This way, you can easily refer to bug fixes at different stages and improve the overall quality of the code. 

Another crucial part of the process is to ensure that authors have left all the necessary comments before you begin the review. Doing so is a code review best practice that goes a long way in ensuring smooth reviews. Checking once with the developer or team before beginning your review can help avoid hiccups at later stages of the review. Comments that defend the logic behind modifications can greatly help the quality of the review. 

2. Use Code Review Checklists While Reviewing

Using checklists is one of the most effective code review techniques and leads to excellent results. Code checklists are the absolute key if you want to make sure everything about the review is satisfactory. Omitting a crucial process from the list of things to do while reviewing code can lead to defects going unnoticed and unidentified, creating unwanted problems in the future.

By using a comprehensive code review checklist, you can eliminate missing out on important aspects of the review and define the review’s expectations. Checklists also serve as great tools if multiple code reviewers are collaborating to review multiple lines of code. 

Each person on your team likely makes the same ten mistakes over and over. Omissions, in particular, are the hardest defects to find because it's difficult to review something that isn't there. Checklists are the most effective way to eliminate frequently made errors and combat omissions. Code review checklists also provide team members with clear expectations for each type of review and can be helpful to track for reporting and process improvement purposes.

3. Do Not Review Code for More Than 60 Minutes at a Time

An important code review best practice is to refrain from reviewing code for too long. The question of how many lines of code do you review in one sitting is a popular code review interview question. 

If you want to know how to review code better, a thumb rule is to avoid overstretching it. Reviewing code too quickly because of time constraints has its drawbacks. But what about reviewing code for too long? Well, that’s just as bad. Ideally, you shouldn’t review code for more than 60 to 90 minutes at a stretch. Multiple studies have shown that taking timely breaks while reviewing code massively improves the quality of the review. 

It is natural for performance to decline if a mentally intense task is performed for over 60 to 90 minutes. Taking frequent breaks while reviewing, ideally once every hour, has shown to greatly improve the quality of code reviews, leading to better code reviews in the future as well.

4. Consider the Security Implications While Suggesting Fixes

It is crucial to completely understand the security ramifications while making changes to source codes. Using a tool that has a record of fixes made by other reviewers and evaluating those fixes is a great way to understand better how security is impacted. 

There are some habits that you must follow to become a successful software developer. Read this article to learn more.

5. Inspect Fewer Than 500 Lines of Code in an Hour

It is standard practice for code to go through multiple stages of review. This essentially implies that if you miss spotting a few errors, it will most likely be rectified by someone else at a later stage of the review (you should attempt to fix over 95% of code errors during your review). But that doesn’t mean you should ignore parts of your responsibility, either knowingly or unknowingly. This is where we introduce another vital code review best practice that leads to better code reviews. 

A SmartBear study of reviewers who reviewed over 500 lines of code within the hour’s mark found a massive drop in the defect density compared to reviewers who reviewed 200 to 400 lines of code in 60 to 90 minutes. 

This indicates that reviewing reasonably lesser LOCs (200 to 400) in more time improves the efficacy of the review. So make sure you follow this code review best practice if you want to review code better. 

6. Review Fewer Than 400 Lines of Code at a Stretch

Reviewing fewer than 400 lines of code is one of the most critical code review best practices to become a better code reviewer. Multiple studies, including a recent SmartBear survey of the programming team at Cisco Systems, indicate that code reviewers shouldn’t review more than 400 lines of code at a Time. The study was closely related to understanding the brain’s ability to effectively process information to ensure that the review is conducted optimally. Reviewing over 400 lines of code (LOC) at a time drastically diminishes the brain’s ability to detect defects in the code accurately. 

Ideally, in order to ensure that your review is of the highest quality, make sure to review anywhere between 200 to 300 lines of code over 90 minutes. This will result in a healthy defect discovery of up to 90%, improving the efficacy of the review as well as the code in general.

FAQs on Code Review 

Q1. What are the steps involved in code review to review code better?

There are many steps involved in code review. The first step is defining the workflow and requesting a review when the branch code is ready for review. The next step is to review the code and submit relevant feedback to the developers. The third step is to do a final round of review after receiving the modified code from the developers. 

Q2. What is the coding best practice around how many lines of code you should review at a time?

You should stick to reviewing not more than 400 lines of code at one stretch. That’s because if you go past the limit, there's a higher probability of making errors while reviewing. Always remember to focus on quality rather than quantity while reviewing.

Q3. How much time should you spend reviewing code before taking a break?

Ideally, you shouldn’t spend more than 90 minutes reviewing code at one stretch. That’s because you’re likely to make errors as the mental burden of code review kicks in. Stick to reviewing code for not more than 60 minutes before taking a break in order to perform better code reviews. 

Q4. When exactly should a code review be done?

An important code review best practice is to review the code when all the automated checks are complete. As the review process isn’t usually completed in a single step, performing your review after the automated checks are done will add more value to the review while also making the review easier and less burdensome. 

Q5. Should code review happen before or after QA?

Ideally, all stages of the code review should happen before the code is passed onto QA. That’s because once the code has passed QA, making internal code-related changes will only repeat the iterative process.

Get Ready for Your Next Coding Interview!

If you want to get started with your interview prep and wish to give it your best shot, register for Interview Kickstart’s FREE webinar to understand the best way to prepare for a code review interview at the biggest companies. 

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We’ve trained thousands of engineers to land dream offers at top tech companies, including Google, Facebook, Amazon, Apple, Microsoft, and Netflix, among others. Check out some reviews to know more.

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Posted on 
November 24, 2021

Dipen Dadhaniya

Engineering Manager at Interview Kickstart

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