Version control integration

Use pre-commit. Once you have it installed, add this to the .pre-commit-config.yaml in your repository:

repos:
  # Using this mirror lets us use mypyc-compiled black, which is about 2x faster
  - repo: https://github.com/psf/black-pre-commit-mirror
    rev: 26.3.1
    hooks:
      - id: black
        # It is recommended to specify the latest version of Python
        # supported by your project here, or alternatively use
        # pre-commit's default_language_version, see
        # https://pre-commit.com/#top_level-default_language_version
        language_version: python3.11

Feel free to switch out the rev value to a different version of Black.

Note if you'd like to use a specific commit in rev, you'll need to swap the repo specified from the mirror to https://github.com/psf/black. We discourage the use of branches or other mutable refs since the hook won't auto update as you may expect.

Jupyter Notebooks

There is an alternate hook black-jupyter that expands the targets of black to include Jupyter Notebooks. To use this hook, simply replace the hook's id: black with id: black-jupyter in the .pre-commit-config.yaml:

repos:
  - repo: https://github.com/psf/black-pre-commit-mirror
    rev: 26.3.1
    hooks:
      - id: black-jupyter
        language_version: python3.11

The `black-jupyter` hook became available in version 21.8b0.

See the Jupyter Notebooks guide for more details.

Excluding files with pre-commit

When using pre-commit, there's an important distinction in how file exclusions work. Pre-commit passes files directly to Black via the command line, rather than letting Black discover files recursively. This means Black's --exclude option won't work as expected because it only applies to files discovered during recursive directory traversal.

To exclude files when using pre-commit, you have two options:

Option 1: Use pre-commit's exclude (Recommended)

Configure exclusions directly in .pre-commit-config.yaml:

repos:
  - repo: https://github.com/psf/black-pre-commit-mirror
    rev: 26.3.1
    hooks:
      - id: black
        exclude: ^migrations/|^generated/

This is the recommended approach because pre-commit filters files before passing them to Black, avoiding unnecessary processing.

Option 2: Use Black's force-exclude in pyproject.toml

Black's force-exclude configuration option excludes files even when they are passed explicitly as command-line arguments (which is how pre-commit invokes Black). Simply add the pattern to your pyproject.toml:

[tool.black]
force-exclude = '''
(
  ^migrations/
  | ^generated/
)
'''

Black automatically reads this configuration—no additional CLI arguments are needed in your .pre-commit-config.yaml.

The `force-exclude` option was added in version 20.8b0 specifically to support
workflows where files are passed directly via CLI, such as pre-commit hooks and
editor plugins.