Vermin

A tool for determining the minimum Python version required to run your code, based on the syntax and standard libraries used.

What is it used for here?

!

analyzing the minimal required Python version for running your code

Important

Vermin analyzes only your code's syntax and use of the standard library.

!

If you use external libraries that require newer Python versions, Vermin will not detect this. It does not check dependencies from requirements.txt or pyproject.toml.
In this template, Vermin is used exclusively in CI via GitHub Actions to ensure code backward compatibility.

How to use it?

There is no need to run Vermin manually or set it up locally — it is integrated into the CI workflow and runs automatically in GitHub Actions.
But of course, you can run it locally directly in your terminal or using pre-commit hook.

Examples

!

Locally (terminal):Pre-commit hook:Github Actions:

uv run vermin --eval-annotations --backport typing --no-parse-comments .

--eval-annotations - evaluates type annotations to determine the minimum Python version.
--backport typing - backports the typing module to older Python versions.
--no-parse-comments - ignores comments in the code, focusing only on actual code syntax.
. - specifies the current directory as the target for analysis.
You can also specify a specific file or directory instead of . to analyze only that part of your codebase.

.pre-commit-config.yaml

- repo: local
  hooks:
    # Run Vermin.
    - id: vermin
      name: vermin
      entry: uv run vermin .
      language: system
      types: [python]
      pass_filenames: false
      args: [ --eval-annotations, --backport typing, --no-parse-comments ]

.github/workflows/compatibility.yml

jobs:
  compatibility:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v4
        with:
          python-version: "3.13"
      - name: Install dependencies
        run: |
          pip install --upgrade pip
          pip install vermin
      - name: Check minimal Python version
        run: vermin --eval-annotations --backport typing --no-parse-comments .

Configuration

Vermin does not have its own configuration file — all parameters are set via the command line.

For more details on configuration, see the Vermin Documentation