Code Review Checklist Template: Standards for Engineering Teams
Code reviews are one of the most important activities on an engineering team, yet most teams do them poorly. Reviews either devolve into nitpicking style preferences, or they become rubber-stamp approvals that miss real issues. Both failure modes erode trust and code quality.
A checklist solves this by making expectations explicit. When every reviewer knows what to look for, reviews become faster, more consistent, and more educational. As a tech lead, establishing clear code review standards is one of the first things you should do — it shapes your team's engineering culture more than almost any other practice.
Why Checklists Beat Intuition
Experienced developers often resist checklists. They feel patronizing. But research consistently shows that even experts miss things under time pressure. A checklist is not a replacement for judgment — it is a safety net that ensures the basics are covered so your judgment can focus on the hard problems.
At one of my previous companies, we introduced this checklist after a security vulnerability slipped through three reviews. The issue was not that our reviewers were incompetent. It was that nobody had explicitly agreed that security was part of the review scope. The checklist made implicit expectations explicit, and we never had that class of issue again.
A code review checklist is a team agreement about what "good enough" looks like. It reduces subjective debates and helps junior developers contribute meaningful reviews from day one.
CODE REVIEW CHECKLIST TEMPLATE
For the PR Author (before requesting review)
- PR description explains WHAT changed and WHY (not just HOW)
- PR is focused on a single concern (not mixing feature, refactor, and bug fix)
- PR size is under 400 lines of meaningful changes (split larger PRs)
- Self-review completed: you have read your own diff line by line
- All tests pass locally and in CI
- New code has appropriate test coverage
- Documentation updated if behavior or API changed
- No temporary code, TODOs without tickets, or commented-out code
- Screenshots or recordings included for UI changes
For the Reviewer: Functionality
- Does the code do what the PR description says it does?
- Are edge cases handled (null values, empty lists, boundary conditions)?
- Are error cases handled gracefully (not just the happy path)?
- Does the logic match the acceptance criteria or ticket requirements?
- Are there any race conditions or concurrency issues?
For the Reviewer: Security
- No secrets, API keys, or credentials in the code
- User input is validated and sanitized
- SQL queries use parameterized statements (no string concatenation)
- Authentication and authorization checks are present where needed
- Sensitive data is not logged or exposed in error messages
- Dependencies are from trusted sources with no known vulnerabilities
For the Reviewer: Performance
- No N+1 query patterns (especially in loops that hit the database)
- Database queries have appropriate indexes
- Large datasets are paginated, not loaded entirely into memory
- Caching is used where appropriate (and cache invalidation is handled)
- No unnecessary network calls or I/O operations in hot paths
For the Reviewer: Readability and Maintainability
- Code is self-documenting: variable and function names describe intent
- Complex logic has explanatory comments (the WHY, not the WHAT)
- Functions are focused and reasonably sized (under 30-40 lines as a guideline)
- Code follows team conventions and style guides
- No unnecessary duplication (DRY, but not at the expense of clarity)
- Abstractions are appropriate: not too early, not too complex
For the Reviewer: Testing
- New functionality has unit tests
- Edge cases and error paths are tested
- Tests are readable: clear setup, action, and assertion
- Tests do not depend on execution order or external state
- Integration tests are present for critical paths
- Test names describe the expected behavior
For the Reviewer: Architecture
- Changes align with the team's architectural patterns
- New dependencies are justified and discussed with the team
- API contracts are backward-compatible (or migration plan exists)
- Changes do not introduce circular dependencies
- Configuration is externalized, not hardcoded
Review Outcome
- Approve: Code meets all critical criteria. Minor suggestions are optional.
- Request Changes: Specific issues must be addressed before merge. List them clearly.
- Comment: Questions or suggestions that do not block the merge.
How to Introduce This Checklist to Your Team
Do not drop this checklist on your team as a mandate. Instead, bring it to a retrospective or team meeting as a proposal. Walk through each section and ask the team to add, remove, or modify items. When the team has ownership over the checklist, they follow it. When it is imposed, they resent it.
Start with the essential sections (Functionality, Security, Testing) and add Performance and Architecture checks once the team is comfortable with the process.
Keeping Reviews Healthy
- Set a turnaround time SLA. Reviews should happen within 4 business hours. Stale PRs kill velocity.
- Separate style from substance. Automate style checks with linters and formatters. Humans should review logic, not indentation.
- Teach, do not lecture. Frame feedback as questions: "What happens if this list is empty?" is better than "You forgot to handle empty lists." Learn more about leading without micromanaging.
- Praise good code. Leave positive comments when you see clean abstractions, good test coverage, or clever solutions. Reviews should not be exclusively critical.
Elevate Your Team's Engineering Standards
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