What it does
Ruff is a Python linter and formatter that can be added to a project environment and configured in pyproject.toml or a Ruff-specific file. The official tutorial demonstrates lint diagnostics, automatic fixes, and formatting as separate tasks. It suits Python teams that want repeatable code-quality checks without treating a style check as a substitute for type checking or behavioral tests.
Ruff's tutorial walks through integrating it into a small Python project. It adds Ruff as a development dependency, runs ruff check on a source file, and then uses the formatter. The example catches an unused import and shows that a fix can be applied automatically. Configuration can live in pyproject.toml, ruff.toml, or .ruff.toml. Keeping the selected rule set beside the source makes local edits and continuous checks easier to reproduce. A useful first pass is to run the linter on one package, review each diagnostic, and enable automatic fixes only when the change is understood; formatting can then be applied as its own step. Ruff's role is code quality, not static type checking or test execution. The existing mypy project answers a different question by checking annotated Python types, while Ruff reports lint rules and formatting differences. Ruff is MIT-licensed, and its documentation describes setup for a local Python project rather than a hosted service.
Strengths
- The linter can identify common issues and offers automatic fixes for supported diagnostics.
- The formatter and linter can share configuration in pyproject.toml or a Ruff-specific file.
- The official tutorial demonstrates adding Ruff as a development dependency to a Python project.
Watch out for
- Ruff checks lint and formatting rules; it does not replace a Python type checker or tests of program behavior.
Best for
- Python projects that want a repeatable linter and formatter in local development or automation.
- Teams migrating lint and format rules into a shared project configuration.
- Code reviews that benefit from automated unused-import and style diagnostics.
Sources
- Ruff (Oct 25, 2026)
- Tutorial (Oct 25, 2026)
- Configuring Ruff (Oct 25, 2026)
- astral-sh/ruff (Oct 25, 2026)
- MIT License (Oct 25, 2026)