Ruff
Extremely fast Python linter and formatter that replaces most of the toolchain.
What it is
Ruff is a Rust-based Python linter implementing rules from Flake8, isort, pydocstyle, pyupgrade, Bandit and dozens of plugins, plus a formatter compatible with Black — typically 10 to 100 times faster than the tools it replaces. It has become the default in new Python projects with unusual speed.
Best for
Where it is strong
- 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.
Where it falls short
- 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.
Pricing
Free and open source
Open sourceFree tier: Everything, self-hosted
What drives the bill: Free and open source. You pay in engineering time and CI minutes.
Check current pricing on Astral’s siteFigures are indicative and were last reviewed August 2026. Vendors change pricing often; confirm before you commit.
Works with
What people who use Ruff say
No reviews of Ruff yet. If you have used it in anger, yours would be the first.
Alternatives to Ruff
If Ruff is not the right fit, these solve the same problem differently.
