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By Pavel Kukhnavets

Code Review

How to apply code review best practices with proper tools.

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Programmers or software development managers may often ignore the benefits of code reviews (or code inspections) at their own risk.

If Agile software development teams pay enough attention to code reviews, they may significantly save time, streamline the development process, and decrease the amount of work required later by QA teams.

Code review is an important part of the software development process. It is usually conducted before merging a new piece with the codebase. In this post, we clearly explain what code review is, define its key benefits and share some reliable code review tools that will assist you with the code review process.

What is the code review process?

What Is a Code Review?

The process of a code review (or a peer code review) is aimed to assess any new code for bugs, errors, and quality standards set by a company. This process should not consist of only one-sided feedback. The real benefit of code review is the improved coding skill of the whole team.

How does it work? When one software developer has finished working on a certain task, another developer looks over the code and considers if there are logic errors in the code, whether all cases are fully implemented, if the new code conforms to existing style guidelines, and so on.

To run a code review process in your company, you should first decide who would review the code. If you represent a small team, you may select a team lead to review all code. In case you are a part of a large team with multiple reviewers, you may enable a process where every code review is assigned to an experienced developer based on his/her workload.

The software code review process should integrate with a team’s existing process.

Why Is This Process Important?

Code reviews are critical as they are never a part of the formal curriculum in educational institutions. The truth is that the code review process evolves as an organization ages.

The process is important for the following reasons:

  • It minimizes the chances to have issues.
  • It ensures that you have no bugs in the code.
  • It confirms new code adheres to guidelines.
  • It boosts the efficiency of new code.

The process of code review also leads to improving other team members’ expertise. As a senior developer usually runs a code review, a junior developer can use this feedback to improve his/her own coding skills.

The Benefits for Agile Teams

Code reviews may benefit any team no matter what development methodology it utilizes. Agile teams get real advantages because work is decentralized across the team. The software code review process helps to facilitate knowledge sharing across the code base and across the team.

So what’s in it for Agile teams?

Sharing knowledge

All agile teams are based on unbeatable flexibility. This is about the ability to take work off the backlog and begin execution by all team players. As a result, they can start new work because no one is on the critical path. Full-stack engineers are able to perform front-end work and server-side work.

Getting better estimates

Estimation is a team effort. As new features are added to the existing code, the developer can provide estimation and feedback. Code reviewers share the knowledge of the developer of that part of the codebase. This practice creates multiple informed inputs that make that estimate stronger and more reliable.

Enabling time off

Being the only point of contact on a piece of code is not the luckiest fate everyone dreams of. Likewise, nobody wants to deal with a critical piece of code they didn’t write (especially during an emergent situation while production).

Code reviews share knowledge across the team. That is why any team member can take the initiative and continue managing the code. However, with no single developer on the critical path, it also means people in the team can take time off as needed. The code review process is a good way to find freedom when you find yourself tied to a desk on the version control system.

Mentoring newer engineers

According to the Agile philosophy, when new members join the team, more experienced engineers mentor the newer members. Code reviews is a great tool to facilitate conversations about the codebase. By the way, teams often have hidden knowledge within the code that surfaces during code review.

Code review

What Are the Common Code Review Approaches?

How to perform a code review? Let’s consider four ways to do it.

1. The Email thread

When a given piece of code is ready for review, colleagues receive the file via email with a request to review it as soon as their workflow permits. This process might certainly be more adaptive and flexible than more traditional approaches. The email thread of suggestions and opinions tends to get complicated fast, leaving the original coder on his/her own to sort through it all.

2. Pair programming

This method of writing software puts developers side by side, working on the same code together and checking each other’s work. This is actually one of the hallmarks of XP (Extreme Programming). This suits senior developers to mentor junior colleagues. However, as authors tend to be too close to their own work, other approaches to code review may provide more objectivity.

3. Tool-assisted

Perhaps, there is arguably no more effective and simpler way to review code than through software-based code review tools. Some of them are browser-based or seamlessly integrate within standard IDE and SCM development frameworks.

Special software solve many limitations, tracking colleagues’ comments and requested solutions to defects in a coherent and clear sequence. This enables reviews to happen asynchronously and non-locally.

4. Over-the-shoulder

The informal over-the-shoulder method is the easiest and most intuitive way for most developers to engage in peer code review (in comparison with the Pair programming).

When the code is ready, you should find a qualified colleague to sit down at your workstation and review your code for you. And that’s it!

Defining the Code Review Best Practices

Remember that reviews are all about collaboration, not competition.

Here are the essential code review best practices you should follow:

1. What to consider during the code review process

It’s critical to go into reviews knowing what to look for in a code review. You have to look for key things, such as structure, logic, style, performance, design, readability, and functionality.

Perform automated checks for some of the things (for example, structure and logic). However, other things (for example, design and functionality) require a human reviewer to evaluate. A proper code reviewing will help you focus on the right things.

2. Build and test before reviewing

The modern Continuous Integration reality requires building and testing before doing a manual review. After tests have passed, you should conduct a review and deploy it to the dev code line. Doing automated checks will help you to cut down on errors and save time in the review process.

3. Don’t review code for longer than 1 hour

It is not a good idea to review code for longer than 1 hour at a time. Attention to detail and performance tends to drop after that point. Instead, it’s better to run reviews often in short sessions.

4. Check no more than 400 lines at a time

Reviewing too many lines of code at once will lead to missing details. So try to keep each review session to 400 lines or less. Setting a line-of-code (LOC) limit will ensure you are at your best when reviewing the code.

5. Give positive feedback

Be constructive in your feedback but not critical. Ask appropriate questions, rather than make statements. Also, remember to praise alongside constructive feedback.

Making your code review better

Start with a good, then make it even better! Good code reviews require many efforts going into them. The process involves a thorough review of the change itself, making nitpicks clear, and avoiding being opinionated with the tone of comments.

Reviewers maintain a consistent bar and try to make cross-time zone reviews less painful. Companies that have positive reviews ensure that every developer regularly receives and does code reviews. Remember that a code review is a great way to improve your skills, mentor others, and learn how to be a more efficient communicator.

Here are some more tips:

  • Start looking at changes at a high level and improve details. It will help you to get better code reviews.
  • Make code reviews welcoming for new starters. Look for systemic solutions for painful cross-time zone reviews.
  • Think of ways outside the code review process to eliminate frequent nitpicks.

The importance of code review tools

Increased efficiency is what can be considered the core outcome of a code review process. Code review tools were designed to automate the process of code review to let reviewers solely focus on the code. These software solutions integrate with the development cycle to initiate a review before new code is merged into the main codebase.

Today you may find an appropriate tool that will be compatible with your technology stack to integrate it into your workflow. For example, if you use Git for code management, ensure that you pick up a tool that supports this technology to be able to fit into the development process.

There are two kinds of code testing in software development:

  • Dynamic analysis involves checking if the code follows special rules and running unit tests.
  • Static code testing is done after a developer generates a new code to be merged into the current code.

What are the most powerful code review tools?

Here we’ve selected just some interesting and reliable tools you may pay your attention to:


Code reviews are important because they make your codebase more stable and improve code quality. These sessions help programmers to work together more effectively and build new relationships. All good code review practices ensure that the process is always free of threats and vulnerabilities.
The code review process is a very important stage for project development. Don’t forget to include checklists and the review of each change and always try to keep up to date with new threats.