Code Review Best Practices
Code review is the most effective quality gate in software development — catching bugs, sharing knowledge, maintaining code standards, and distributing understanding of the codebase. Done well, it improves quality significantly. Done poorly, it creates friction, slows delivery, and damages team relationships.
What Code Review Is For
- Bug detection: A second pair of eyes catches mistakes the author is blind to
- Knowledge sharing: Reviewers learn about changes; authors learn from reviewer insights
- Consistency: Enforcing code style, architecture patterns, and standards
- Mentoring: More experienced reviewers develop less experienced authors
Code Review Is Not For
Style enforcement (use a linter), approval bureaucracy (one reviewer is usually sufficient), or the reviewer to redesign the author's implementation. Nitpicking trivial style issues in a review that misses a critical bug is a waste of everyone's time.
How to Review Well
- Review the right things: correctness first, then design, then style
- Be constructive: "This could lead to a null pointer exception when X happens" is better than "This is wrong"
- Ask questions rather than making demands: "Have you considered X?" invites discussion
- Distinguish between blocking issues and suggestions: use labels (blocking/non-blocking/nit)
- Review promptly — sitting on review requests for days slows the team
Pull Request Size
Smaller PRs receive better reviews. A 200-line change is reviewed carefully; a 2,000-line change is rubber-stamped. Break work into small, reviewable pieces.