What to Look for in a Code Review

Code reviews are an essential part of software development. They help ensure that code is well-designed, functional, and meets the needs of the users. However, code reviews can be time-consuming and challenging, and it can be challenging to know what to look for. In this article, we’ll provide a guide for software engineers on what to look for in a code review.

Design and Functionality

When reviewing code, it’s essential to pay attention to the design and functionality. Is the code well-designed? Does it meet the needs of the users? Are any UI changes sensible and look good? These are all critical questions to ask during a code review.

Parallel Programming and Complexity

Another essential aspect of code review is ensuring that any parallel programming is done safely and that the code isn’t more complex than it needs to be. Developers should avoid implementing things they might need in the future but don’t know they need now. It’s important to keep the code as simple as possible while still meeting the needs of the users.

Unit Tests and Documentation

Unit tests and documentation are also essential components of code review. Code should have appropriate unit tests, and tests should be well-designed. The developer should use clear names for everything, and comments should be clear and useful. Documentation should be appropriately documented in g3doc.

Style Guide and Consistency

The code should conform to the style guides, and the developer should maintain consistency with existing code. If the existing code is inconsistent with the style guide, the new code should follow the guidelines. Documentation should be updated if the PR changes how users build, test, interact with, or release code.

Every Line and Context

During a code review, it’s crucial to look at every line of code. It’s also essential to consider the PR in the context of the system as a whole. Is this PR improving the code health of the system, or is it making the whole system more complex and less tested? Don’t accept PRs that degrade the code health of the system.

Exceptions and Good Things

There may be exceptions to reviewing every line of code, such as when only certain files are part of a larger change or when only certain aspects of the PR are being reviewed. If you see something nice in the PR, tell the developer, especially when they addressed one of your comments in a great way.


Code reviews are a critical part of software development, and software engineers should pay close attention to the design and functionality, parallel programming and complexity, unit tests and documentation, style guides and consistency, and every line and context. By following these guidelines, software engineers can ensure that their code is well-designed, functional, and meets the needs of the users.