Writing Commit Messages

Write commit messages that are useful for humans and machines.

Format

<type>(<optional scope>): <subject>

<optional body>

<optional footer>

Subject Line Rules

• 50 characters or less for the subject
• Use imperative mood: "add feature" not "added feature" or "adding feature"
• Don't capitalize the first letter after the type prefix
• No period at the end

Types

Type	When to use
feat	New user-facing feature
fix	Bug fix
refactor	Code restructuring without behavior change
docs	Documentation changes
test	Adding or updating tests
chore	Build, CI, tooling, deps
perf	Performance improvement
style	Formatting, whitespace (not CSS)
ci	CI/CD pipeline changes
revert	Reverting a previous commit

Scope (Optional)

The area of the codebase affected:

• feat(auth): add OAuth2 login flow
• fix(api): handle null response from payments endpoint
• refactor(db): extract query builder into module

Body (When Needed)

Explain why, not what (the diff shows what):

fix(checkout): prevent duplicate order submissions

The submit button was not disabled after the first click,
allowing users to create multiple orders. This caused
duplicate charges in Stripe.

Footer (When Needed)

BREAKING CHANGE: rename `getUserById` to `findUser`

Closes #456
Co-authored-by: Name <email>

Examples

Good:

feat(dashboard): add real-time notification bell
fix: resolve race condition in WebSocket reconnect
refactor(api): consolidate error handling middleware
test: add integration tests for payment webhook
chore: upgrade TypeScript to 5.4

Bad:

fixed stuff
WIP
update
changes
asdf

When to Commit

• Each commit should represent one logical change
• Don't mix refactoring with feature work in the same commit
• Don't commit half-working code (use git stash instead)
• Commit early and often on feature branches, squash before merge if needed

Breaking Changes

If the commit introduces a breaking change:

1. Add ! after the type: feat(api)!: change auth token format
2. Add BREAKING CHANGE: in the footer with migration instructions