What Is a Code Review? Explained Simply

What a code review is

A code review is the practice of having one or more developers examine another developer's code before it is merged into the main codebase. The goal is to catch bugs and problems early, improve the quality and consistency of the code, and share knowledge across the team. Code review is a standard practice on most professional software teams, a quality checkpoint where human eyes review changes before they become part of the project. It is collaboration and quality control rolled into one.

How it works

Typically, when a developer finishes a piece of work, they submit their changes for review, often as a 'pull request' in a version control system. One or more teammates then read through the changes, leave comments, ask questions, and suggest improvements. The author responds, makes adjustments, and once the reviewers are satisfied, the code is approved and merged. This back-and-forth happens before the code joins the shared codebase, catching issues while they are still easy to fix.

What reviewers look for

Reviewers check for many things: bugs and logic errors, whether the code is clear and maintainable, whether it follows the team's conventions, potential security or performance issues, and whether it actually does what it is supposed to. A good review is constructive, focused on improving the code rather than criticizing the person. The reviewer brings a fresh perspective that the author, close to their own work, may lack, often spotting issues the author missed.

Benefits beyond bugs

While catching bugs is a key benefit, code review offers much more. It spreads knowledge: reviewers learn about parts of the codebase they did not write, reducing the risk of only one person understanding critical code. It helps maintain consistent quality and style across the team. It mentors less experienced developers through feedback. And it creates shared ownership of the code. These collaborative and knowledge-sharing benefits are often as valuable as the bug-catching itself.

Doing reviews well

Effective code review depends on good practices and culture. Reviews work best when changes are reasonably small (so they are easy to review thoroughly), when feedback is kind and constructive, and when both authors and reviewers treat it as a shared effort to improve the code, not a personal judgment. A healthy review culture improves both the software and the team. Done poorly, reviews can feel adversarial; done well, they strengthen quality and collaboration together.

Why it matters

Code review is a cornerstone practice of professional software development, improving quality, catching problems early, and spreading knowledge across a team. Understanding it clarifies how teams maintain healthy codebases, why changes are checked before merging, and how collaboration contributes to better software. For anyone interested in how quality software is built by teams, the code review is an essential and widely practiced concept.

Related on Skillo

See also: What is version control? Explained for beginners, What is a Git branch? Explained simply.

Sources

• Code review - Wikipedia

Published date reflects the original event date (2023-10-24). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.