Code Review Checklist

Review Priority Order

1. Security (Critical) - Vulnerabilities, secrets, injection
2. Correctness (High) - Logic errors, breaking changes
3. Performance (Medium) - Inefficiencies, resource leaks
4. Quality (Medium) - Maintainability, readability
5. Style (Low) - Formatting, naming (should be automated)

Security Checklist

Secrets & Credentials

• No hardcoded API keys, passwords, tokens
• No credentials in logs or error messages
• Secrets loaded from environment/vault

Injection Vulnerabilities

• SQL queries use parameterized statements
• User input is sanitized before HTML output (XSS)
• Shell commands don't include user input (command injection)
• File paths are validated (path traversal)

Authentication & Authorization

• Auth checks on all protected endpoints
• Proper session handling
• Secure password handling (hashing, not plaintext)

Data Exposure

• Sensitive data not logged
• API responses don't leak internal details
• Error messages don't expose system info

Correctness Checklist

Logic

• Edge cases handled (null, empty, boundary values)
• Error conditions handled appropriately
• Async operations properly awaited
• Race conditions considered

Breaking Changes

• API contracts maintained
• Database migrations are reversible
• Feature flags for risky changes

Testing

• New code has tests
• Tests cover error paths, not just happy path
• Existing tests still pass

Performance Checklist

Efficiency

• No N+1 queries
• Appropriate data structures used
• No unnecessary loops or iterations
• Caching considered for expensive operations

Resources

• Database connections closed/pooled
• File handles closed
• No memory leaks (event listeners removed, etc.)

Scale

• Works with realistic data volumes
• Pagination for large result sets
• Timeouts on external calls

Quality Checklist

Readability

• Clear, descriptive names
• Functions do one thing
• No overly complex conditionals
• Comments explain "why", not "what"

Maintainability

• DRY (no copy-paste duplication)
• Appropriate abstractions
• Dependencies are justified
• No dead code

Consistency

• Follows project patterns
• Matches existing code style
• Uses established utilities/helpers

Review Output Format

## Review: [PR Title]

**Risk Level**: LOW | MEDIUM | HIGH | CRITICAL

### Critical Issues
1. [Category] Description (file:line)
   - Impact: What could go wrong
   - Fix: Specific recommendation

### Suggestions
1. [Category] Description (file:line)
   - Why: Reasoning
   - Consider: Alternative approach

### Positive Notes
- [Recognition of good patterns]

Quick Checks

1. Any secrets or credentials?
2. Any SQL/command injection?
3. Are error cases handled?
4. Do tests exist for new code?