Git commit message

To write a great git commit message, take a look at these guidelines and suggestions.

Contents:

• Top priorities
• Begin with a short summary line
• Continue with a longer description
• Summary examples
• Summary keywords
• Real-world examples
• Use semantic versioning
• Specifics for right and wrong
• Specifics for length
• Reasoning
• Reject these formats
• Optional: use contact email addresses
• Optional: use task tracking links
• Optional: use resource tracking metrics
• Optional: use keywords, importance, references, etc.
• Related links

Top priorities

For the best git commit messages:

• Read these guidelines and suggestions, then discuss them with your teammates.

• Emphasize clear communication, because commit messages help you and your teammates.

• Use a git commit template, such as ours here.

Begin with a short summary line

Begin with a short summary line a.k.a. message subject:

• Start with an imperative present active verb: Add, Drop, Fix, Refactor, Optimize, etc.

• Use up to 50 characters; this is the git official preference.

• Finish without a sentence-ending period.

Continue with a longer description

Continue with a longer description a.k.a. message body:

• Add a blank line after the summary line, then write as much as you want.

• Use up to 72 characters per line for typical text for word wrap.

• Use as many characters as needed for atypical text, such as URLs, terminal output, formatted messages, etc.

• Include any kind of notes, links, examples, etc. as you want.

Summary examples

Summary examples of good commit messages:

• Add foo

• Drop foo

• Fix foo

• Refactor foo

• Optimize foo

Summary keywords

We recommend these summary keywords because they use imperative mood, present tense, active voice, and are verbs:

• Add: Create a capability e.g. feature, test, dependency.

• Drop: Delete a capability e.g. feature, test, dependency.

• Fix: Fix an issue e.g. bug, typo, accident, misstatement.

• Bump: Increase the version of something e.g. a dependency.

• Make: Change the build process, or tools, or infrastructure.

• Start: Begin doing something; e.g. enable a toggle, feature flag, etc.

• Stop: End doing something; e.g. disable a toggle, feature flag, etc.

• Optimize: A change that MUST be just about performance, e.g. speed up code.

• Document: A change that MUST be only in the documentation, e.g. help files.

• Refactor: A change that MUST be just a refactoring patch

• Reformat: A change that MUST be just a formatting patch, e.g. change spaces.

• Rearrange: A change that MUST be just an arranging patch, e.g. change layout.

• Redraw: A change that MUST be just a drawing patch, e.g. change a graphic, image, icon, etc.

• Reword: A change that MUST be just a wording patch, e.g. change a comment, label, doc, etc.

• Revise: A change that MUST be just a revising patch e.g. a change, an alteration, a correction, etc.

• Refit/Refresh/Renew/Reload: A change that MUST be just a patch e.g. update test data, API keys, etc.

We recommend these summary keywords for things that don't fit into the above categories:

• Major: Anything that causes a major version increase.

• Minor: Anything that causes a minor version increase.

• Patch: Anything that causes a patch version increase.

Real-world examples

Real-world examples show how we use imperative mood, present tense, active voice, and verbs:

• Add feature for a user to like a post

• Drop feature for a user to like a post

• Fix association between a user and a post

• Update dependency library to current version

• Make build process use caches for speed

• Start feature flag for a user to like a post

• Stop feature flag for a user to like a post

• Optimize search speed for a user to see posts

• Document community guidelines for post content

• Refactor user model to new language syntax

• Reformat home page text to use more whitespace

• Rearrange buttons so OK is on the lower right

• Redraw diagram of how our web app works

• Reword home page text to be more welcoming

• Revise link to update it to the new URL

Real-world examples for things that don't fit into the above categories:

• Major overhaul of our API from version 1 to 2

• Minor improvement of our API from version 1.1 to 1.2

• Patch our API from version 1.1.1 to 1.1.2

Use semantic versioning

We use semantic versioning for many of our projects:

• Add, Start: Increment SemVer MINOR version when there is a new capability.

• Drop, Stop: Increment SemVer MAJOR version when there is an incompatibility.

• Fix, Update, Make, Optimize, Document: Increment SemVer PATCH version.

• Refactor, Reformat, Rearrange, Redraw, Reword: Increment SemVer PATCH version.

Specifics for right and wrong

Capitalize the summary.

• Right: Add feature

• Wrong: add feature

Finish the summary without a sentence-ending a period.

• Right: Add feature

• Wrong: Add feature.

If the summary ends with an non-sentence-ending period, use it.

• Right: Add feature for U.S.A.

• Wrong: Add feature for U.S.A

Use imperative mood: present tense, active voice, and lead verb.

• Right: Add feature

• Wrong: Adds feature (this is indicative mood, not imperative mood)

• Wrong: Added feature (this is past tense, not present tense)

• Wrong: Adding feature (this lead is a gerund, not a verb)

• Wrong: Feature added (this is passive voice, not active voice)

Specifics for length

Keep the summary line within 50 characters.

• The purpose is easy readability.

• This is the git official convention.

• This is the same convention as writing an email message.

Use a blank line after the summary line.

• The purpose is making the commit message parseable by tools.

• This is the git official convention.

• This is the same convention as writing an email message.

Use up to 72 characters per line for typical text for word wrap.

• The purpose is easy readability on typical terminals.

• This is the git official convention.

• This is the same convention as writing an email message.

Use as many characters as needed for atypical text, such as URLs, output, formatted messages, etc.

• The purpose is preserving important formatting.

• This is the git official convention.

• This is the same convention as writing an email message.

Reasoning

We primarily care that our team communicates effectively with our shared understanding.

We secondarily like these verbs above because they're easy to read, easy to type, and clear in many cultures.

If you and your team prefer other words, that's fine too; use what works for you.

Reject these formats

We reject git commit message styles that put meta-information into the summary line.

Example:

• [bug] ...

• (release) ...

• #12345 ...

• docs: ...

• JIRA-666 #time 1w 2d 4h 30m #comment Task completed ahead of schedule #resolve

We reject the git commit message style of projects such as Angular, Commitizen defaults, etc.

• Because these use a leading tag that is sometimes a word, sometimes an abbreviation, sometimes a plural noun, etc.

• Examples are using "feat" for feature, "docs" for document, "perf" for performance improvement, etc.

• Instead we use "Add" for adding a feature, "Document" for documenting help, "Optimize" for performance improvement, etc.

• Active verbs are easier to skim, and easier to use for people from other cultures who may be less-comfortable using English.

We reject using a ticket id number in the summary line.

• Instead, we use fully-qualified URLs in the commit message body.

• This is because many of our projects use multiple tracking systems, and multiple ways of launching a URL.

• We want URL tracking to be easy to use by a wide range of systems, scripts, and teams.

We reject using a time tracking syntax in the summary line.

• Instead, if you want time tracking, put the info in the commit message body.

• This is because your personal time tracking is irrelevant to most other developers.

• If you must use time tracking, we recommend the format of ISO 8601 and UTC, such as "YYYY-MM-DDTHH:MM:SSZ"

Optional: use contact email addresses

We sometimes have more than one person working on a commit. For example, we do do pair programming.

To keep track of this, we write a git commit message body that lists each person. We use the person's name and the email address. We use one person per line because this is easy to parse.

Co-authored-by: Alice Adams <alice@eaxmple.com>
Co-authored-by: Bob Brown <bob@example.com>
Co-authored-by: Carol Curtis <carol@example.com>

To make this easy, we use a git commit template.

Optional: use task tracking links

We sometimes connect a git commit to a task tracking system or web page that explains more. For example, we use GitHub, Trello, Jira, and many other bug tracking systems and project management software systems.

To keep track of these, we use a git commit message body that lists each URL, one per line, because this is easy to parse.

Example:

Add feature foo

See: https://github.com/user/repo/issues/789
See: https://jira.com/tasks/123
See: https://wikipedia.com/quicksort

If we want to provide link names, then we use Markdown links, such as:

See: [Request for help with sign in](https://github.com/user/repo/issues/789)
See: [Add feature foo](https://jira.com/tasks/123)
See: [Wikipedia Quicksort](https://wikipedia/quicksort)

To make this easy in practice, we use a git template that helps fill in this info.

Optional: use resource tracking metrics

We sometimes connect a git commit to a resource tracking system or metrics scripts. For example, we work on some projects where the project managers must keep track of work hours spent on a commit, or story point estimates per feature branch, or cost of hiring a developer to fix a bug.

To keep track of these, we use a git commit message body that lists each item, one per line, because this is easy to parse.

Example:

Add feature foo

Time: 7 staff hours
Cost: $700
Points: 7

Optional: use keywords, importance, references, etc.

We like to use commit message keywords to help us skim, search, and prioritize.

To keep track of these, we write a git commit message body that uses email header conventions.

Example:

Fix foo

Keywords: security, encryption, authentication
Importance: high
References: ...
Supersedes: ...
Obsoletes: ...
See-Also: ...

We use some of these to help our teams focus on the most important work.

• When a commit message says "Importance: high" then it gets priority for code review and also for testing on the continuous integration server.

• When a commit message says "Supersedes", "References", "Obsoletes", then we can easily look up the earlier commits or URLs.

Related links

Blog posts about how to write git commit messages:

• 5 Useful Tips For A Better Commit Message by Caleb Thompson at Thoughtbot

• A Note About Git Commit Messages by tpope at tbaggery

• How to Write a Git Commit Message by Chris Beams

• Writing good commit messages by the Erlang OTP team

• On commit messages by Who-T

• Linus Torvalds advice on word wrap

• Writing commit messages by Simon Tatham

Tools that help with git commit messages:

• commitlint: a command line tool to lint git commit messages

• husky: git hooks made easy

• commitizen command line utility

• conventional-changelog: generate changelogs and release notes from a project's commit messages and metadata