Ruff
Astral's Rust linter and formatter for Python; 800+ rules in one binary.
About
Ruff is a Python linter and formatter written in Rust that replaces Flake8, Black, isort, pydocstyle, and dozens of plugins with a single fast binary. It ships more than 800 lint rules, formats code in milliseconds per file, and configures entirely through pyproject.toml. It has become the de facto standard toolchain in the Python ecosystem, reaching hundreds of millions of downloads per month across the Astral suite.
On March 19, 2026, OpenAI announced it would acquire Astral, the company behind Ruff, uv, and the ty type checker, folding the team into its Codex group. OpenAI said it would keep the tools open source after closing, but the deal raised governance questions about the long-term neutrality of tooling now owned by a proprietary coding-agent vendor.
What it can do
- Lint with 800+ rules covering pyflakes, pycodestyle, bugbear, and more
- Format code as a Black-compatible formatter
- Auto-fix violations with ruff check --fix
- CI-ready with fast exit codes and pre-commit support
Setup
Install with pip (pip install ruff), uv (uv tool install ruff), Homebrew, or run without installing via uvx ruff. Add a [tool.ruff] section to pyproject.toml.
Prerequisites
A Python project; optional pyproject.toml for configuration.
Use cases
Works with
Trust score — 9/10
Scored 9/10 (verified tier, metrics-v1). Evidence: Verified via vendor site/docs/GitHub and reputable coverage, wave 93; Trending score 92/100 from researcher assessment.
Sources
Every fact above was checked against these sources. Where a claim comes from the provider and couldn't be independently verified, the text says so.