Code Climate Quality vs Ruff

From $16 per user/month (indicative)

Free and open source

Per-seat pricing; free for public repositories.

Free and open source. You pay in engineering time and CI minutes.

Free for open-source repositories.

Everything, self-hosted

Established

Code Climate · since 2011

Category standard

Astral · since 2022

• Maintainability grading is easy to communicate to non-engineers.
• Coverage and quality tracked together in one PR check.
• Free for open source.

• Replaces Flake8, isort, Black, pyupgrade and more with a single fast binary.
• Fast enough to run on every keystroke in the editor.
• Straightforward migration from existing Flake8 configurations.

• Less depth and fewer languages than SonarQube.
• Letter grades oversimplify and can drive the wrong behaviour.
• Product investment appears to have slowed.

• Not every niche Flake8 plugin rule has been ported.
• Type checking is a separate concern — you still need mypy or ty.
• Rapid release cadence occasionally changes behaviour.

Teams that want a simple maintainability signal in pull requests.

Every Python project.