Code Review

Code Review is the practice where a colleague examines code written by another developer before it is incorporated into the main branch. On GitHub it happens inside Pull Requests.

How it works #

The developer opens a Pull Request with their changes. An assigned reviewer examines the code diff, leaves comments, suggests improvements and eventually approves or requests changes. The process is asynchronous: no meetings needed, the review happens on the tool. Only after approval is the code merged into the main branch.

What it’s for #

Code review catches bugs that automated tests don’t find, improves code quality, and — an often underestimated aspect — spreads codebase knowledge across the team. If only one person knows a module and they leave, the project has a problem. With code reviews, at least two people know every piece of code.

When to use it #

On every Pull Request, without exceptions. It’s not a formality: it’s an investment in quality. Time spent in review is always less than time spent fixing bugs in production discovered too late.