A woman showing the basic checklist for code review

The Ultimate Code Review Checklist

The Ultimate Code Review Checklist

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The code review process is one of those processes that differs from team to team and different standards set by developers. It is a complex process, as seen in an earlier blog, and hence needs a code review checklist that every organization must follow before performing a code review.

This checklist is made for beginners as well as expert developers, stating necessary and an ideal list to do a code review process. This list is language-neutral, and you can use it for most programming languages without having to create significant changes. We made this code review checklist according to the practices that are missed by developers while building software, and hence creating poor quality code. Let’s look at the comprehensive list to do a code review and build clean software.

Things to do before the code review process

There are a few points you need to take care of before performing a code review. These are practices that every team or CTO needs to do after the first draft of the code is complete.

Must read: CTOs outlook on the code review process and how to optimize it for your team?


Setting the design standard is highly essential before beginning the code review process. The team needs to lay down some measures that developers and reviewers must follow while reviewing. Further, the expectation from the software on performance, methods used, technologies implemented, and the result at the output should be noted first. This gives you a reference to check if the code is done in the required way and if not, how far did it deviate from the expectations. 

Lastly, before beginning the code review process, you should always estimate the time required to do all checks in code review. The deadline and time taken to complete a code review are two leading reasons for developers ignoring it. While you don’t wish to miss any step, you should always make sure that you must do checks that are more essential before those that do not contribute significantly to technical debt. Considering if you run out of time, the code would have solutions to significant problems already leaving behind some smells that would not create a bigger problem.

The Complete Code Review Checklist

A woman showing the basic checklist for code review

Check if the code is easily readable, easy to understand, and is highly manageable. You should do the formatting of the code in such a way that it is readable. Significant steps and instructions should be commented on for better understanding, while comments that are blockers should be removed. You can delete all comments and retrieve them from an SVN file if needed. Make sure that you use proper terminology and code is aligned with appropriate spaces. Your code should be able to fit a 14-inch screen so that when imported to other monitors, it is readable.


The code should follow an architecture throughout the whole program to be uniform. The design pattern defined earlier must be the reference when judging architecture. While reviewing if any design changes are required, be sure to document, approach, and baseline it before implementing it. The code needs to be split into different layers – presentation, business, and data layer as per requirement. Code design should resonate with earlier products and software of the same project.


Code review most common aim is the improvement of code quality, making it maintainable. A good quality code has low technical debt and requires the least help in future development and manipulations. For higher code quality, make sure you maintain four factors – code readability, testability, debuggability, and configurability. The code should be easy to read for any developer and must be self-explanatory. The code should be easy to test, in any way possible without failing even at edge cases. For this, try using interfaces while communicating between layers.


This is a check for output producing the ability of code. Test plans should be present and executed, while unit cases should test all edge cases without failure. All the nonobvious logic needs to be covered by tests. There should be no race around the condition.

Invalid input/states

This is a check for input taking the ability of code. Input boxes must handle all arbitrary strings as well. Check for your code’s input parameters – can negatives be included?; what is the range of input?; what type of input is allowed, and if not received what case to follow? Floating-point values should have sufficient precision. If in the case of network loss, handling of the input needs to be done correctly.


Consider yourself as a user of the software that you’re Developing and question yourself if the UI of the software is understandable? Any difficulty found using the software by you, who wrote the code can be a bigger problem for end-users. People rush to the development phase so early that they forget without a usable UI/API software it will result in many errors. If you are not convinced with user interface design, then start working on it with your team.


Reusability of code is a significant factor for reducing your file length and size, saving space, and also making the code much organized. See if any methods or blocks of code are not repeated in your program. Try using generic classes, functions, and components that can be reused. Follow the DRY principle  (Don’t Repeat Yourself) and code with no duplication.

Object-Oriented Analysis and Design (OOAD) Principles

These principles are a few checks that will make your code much more efficient. Remember all these principles are chosen according to your project, and a few may have an inverse relationship where if you follow one, the other gets void. OOAD principles are:

Single Responsibility Principle: All classes should have one responsibility, or just one function in a class or a method.

Open Closed Principle: Existing code should not be altered when new functionality is introduced.

Liskov Sustainability Principle: Having a child class should not change the meaning of the parent class.

Dependency Injection: Create dependencies outside the class and inject them into class in appropriate ways.

Interface Segregation Principle: No client should be forced to depend on methods that it does not use. Instead, create smaller interfaces based on functionality.

A man following the complete code review checklist


Code review is a necessary process that can be done by following these points, which is again a challenge to do manually. To perform all these checks flawlessly, we recommend our code review tool CodeGrip. Codegrip takes care of all the tests mentioned above and many more checks. From minor to major checks, CodeGrip scans all your code and indicates all the errors, code vulnerabilities, and code smells that you can fix to improve your code quality.

If code review is important to you, Sign up for a free trial of our automated code review tool.

The above code review checklist covers all necessary code review checks that one can perform while reviewing. There may be other checks that you can use, but it depends on the requirement and complexity of the project. But following this will make your code error-free, clean and of higher quality. Performing these checks are hard, so using an automated code review tool like CodeGrip gives you an upper advantage.

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