The Ultimate Code Review Checklist for 2026

Code reviews are one of the highest-leverage activities in software development. A systematic checklist ensures nothing important slips through.

Security Checklist

- [ ] No hardcoded secrets (API keys, passwords, tokens)

[ ] User input is validated and sanitized
[ ] SQL queries use parameterized statements
[ ] Authentication/authorization checks are in place
[ ] Sensitive data is not logged or exposed in error messages
[ ] Dependencies are up to date (no known CVEs)

Common Security Misses

// BAD: SQL injection vulnerability

const query = 'SELECT * FROM users WHERE id = ' + userId;
// GOOD: Parameterized query
const query = 'SELECT * FROM users WHERE id = $1';
await db.query(query, [userId]);
// BAD: Leaking sensitive data
console.log('Login:', { email, password, token });
// GOOD: Redact sensitive fields
console.log('Login:', { email, password: '[REDACTED]' });

Performance Checklist

- [ ] No N+1 query patterns

[ ] Database queries use appropriate indexes
[ ] Large lists are paginated
[ ] Expensive operations are cached
[ ] No memory leaks

Maintainability Checklist

- [ ] Functions do one thing (Single Responsibility)

[ ] Variable and function names are descriptive
[ ] No magic numbers — use named constants
[ ] Error handling is comprehensive
[ ] No duplicated code (DRY principle)

The Human Side

1. Be kind: Critique the code, not the person

2. Explain why: Don't just say "change this"

3. Praise good work: Call out clever solutions

4. Keep it small: Review PRs under 400 lines

5. Timebox it: Review within 24 hours

Bookmark this checklist and use it alongside our developer tools at sdk.is.