Ruff — Extremely Fast Python Linter & Formatter

Overview

Ruff is an extremely fast Python linter and code formatter written in Rust. It is designed as a drop-in replacement for Flake8, isort, Black, and many Flake8 plugins — all reimplemented in Rust as first-party features. Ruff supports Python 3.7 through 3.14, ships with 900+ built-in rules, includes an automatic fix mode, built-in caching, Jupyter Notebook support, and a built-in language server for editor integration.

Key Features

• Speed: 10–100x faster than Flake8 and comparable linters, written in Rust.
• Unified toolchain: Linter, formatter, import sorter, and language server in a single binary.
• 900+ rules: Re-implementations of popular Flake8 plugins (flake8-bugbear, flake8-comprehensions, flake8-simplify, pydocstyle, isort, pyupgrade, and many more).
• Formatter: Drop-in replacement for Black with configurable quote style, indent style, line endings, and docstring code formatting.
• Automatic fixes: Many rules are auto-fixable via --fix; unsafe fixes available via --unsafe-fixes.
• Configuration: Supports pyproject.toml, ruff.toml, and .ruff.toml with hierarchical discovery and config inheritance via extend.
• Jupyter Notebooks: Built-in linting and formatting of .ipynb files (v0.6.0+).
• Editor integrations: Built-in language server (ruff server), VS Code extension, Neovim, Vim, Helix, Emacs, PyCharm, Sublime Text, Zed, and more.
• Preview mode: Opt-in to unstable rules and formatting styles before they become stable.
• Shell autocompletion: bash, zsh, fish, elvish, powershell, fig.
• No Rust required: Ships as a standalone binary; installable via uv, pip, pipx, or standalone installers.