GitHub Actions integration

You can use Black within a GitHub Actions workflow without setting your own Python environment. Great for enforcing that your code matches the Black code style.

Compatibility

This action is known to support all GitHub-hosted runner OSes. In addition, only published versions of Black are supported (i.e. whatever is available on PyPI).

Finally, this action installs Black with the colorama extra so the --color flag should work fine.

Usage

Create a file named .github/workflows/black.yml inside your repository with:

name: Lint

on: [push, pull_request]

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6
      - uses: psf/black@stable

We recommend the use of the @stable tag, but per version tags also exist if you prefer that. Note that the action's version you select is independent of the version of Black the action will use.

Versions

The version of Black the action will use can be configured via version or read from the pyproject.toml file. The action defaults to the latest release available on PyPI.

version can be any valid version specifier or just the version number if you want an exact version.

If you want to match versions covered by Black's stability policy, you can use the compatible release operator (~=):

- uses: psf/black@stable
  with:
    options: "--check --verbose"
    src: "./src"
    version: "~= 22.0"

To read the version from the pyproject.toml file instead, set use_pyproject to true. This will first look into the tool.black.required-version field, then the dependency-groups table, then the project.dependencies array and finally the project.optional-dependencies table. Note that this requires Python >= 3.11, so using the setup-python action may be required, for example:

Security note: use_pyproject only accepts standard version specifiers for black (for example ==, ~=, >= and ranges like >=25,<26). Direct references such as black @ https://... are not supported. If your workflow runs on untrusted pull requests (for example from forks), prefer setting with.version explicitly.

- uses: actions/setup-python@v6
  with:
    python-version: "3.13"
- uses: psf/black@stable
  with:
    options: "--check --verbose"
    src: "./src"
    use_pyproject: true

Only versions available from PyPI are supported, so no commit SHAs or branch names.

Jupyter Notebooks

If you want to include Jupyter Notebooks, it can be enabled by setting jupyter to true (default is false):

- uses: psf/black@stable
  with:
    jupyter: true

See the Jupyter Notebooks guide for more details.

CLI Options

You can also configure the arguments passed to Black via options (defaults to '--check --diff') and src (default is '.'). Please note that the --check flag is required so that the workflow fails if Black finds files that need to be formatted.

Here's an example configuration:

- uses: psf/black@stable
  with:
    options: "--check --verbose"
    src: "./src"
    jupyter: true
    version: "21.5b1"