Ruff

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An extremely fast Python linter and code formatter, written in Rust.

• ⚡️ 10-100x faster than existing linters (like Flake8) and formatters (like Black)
• 🐍 Installable via pip
• 🛠️ pyproject.toml support
• 🤝 Python 3.15 compatibility
• ⚖️ Drop-in parity with Flake8, isort, and Black
• 📦 Built-in caching, to avoid re-analyzing unchanged files
• 🔧 Fix support, for automatic error correction (e.g., automatically remove unused imports)
• 📏 Over 900 built-in rules, with native re-implementations of popular Flake8 plugins, like flake8-bugbear
• ⌨️ First-party editor integrations for VS Code and more
• 🌎 Monorepo-friendly, with hierarchical and cascading configuration

Ruff aims to be orders of magnitude faster than alternative tools while integrating more functionality behind a single, common interface.

Ruff can be used to replace Flake8 (plus dozens of plugins), Black, isort, pydocstyle, pyupgrade, autoflake, and more, all while executing tens or hundreds of times faster than any individual tool.

Ruff is actively developed and used in major open-source projects like:

• Apache Airflow
• Apache Superset
• FastAPI
• Hugging Face
• Pandas
• SciPy

Ruff is backed by Astral, the creators of uv and ty.

Read the launch post, or the original project announcement.

Testimonials

Sebastián Ramírez, creator of FastAPI:

Ruff is so fast that sometimes I add an intentional bug in the code just to confirm it's actually running and checking the code.

Nick Schrock, founder of Elementl, co-creator of GraphQL:

Why is Ruff a gamechanger? Primarily because it is nearly 1000x faster. Literally. Not a typo. On our largest module (dagster itself, 250k LOC) pylint takes about 2.5 minutes, parallelized across 4 cores on my M1. Running ruff against our entire codebase takes .4 seconds.

Bryan Van de Ven, co-creator of Bokeh, original author of Conda:

Ruff is ~150-200x faster than flake8 on my machine, scanning the whole repo takes ~0.2s instead of ~20s. This is an enormous quality of life improvement for local dev. It's fast enough that I added it as an actual commit hook, which is terrific.

Timothy Crosley, creator of isort:

Just switched my first project to Ruff. Only one downside so far: it's so fast I couldn't believe it was working till I intentionally introduced some errors.

Tim Abbott, lead developer of Zulip (also here):

This is just ridiculously fast... ruff is amazing.

Table of Contents

For more, see the documentation.

1. Getting Started
2. Configuration
3. Rules
4. Contributing
5. Support
6. Acknowledgements
7. Show Your Support
8. License

Getting Started

For more, see the documentation.

Installation

Ruff is available as ruff on PyPI.

Invoke Ruff directly with uvx:

uvx [email protected] check   # Lint all files in the current directory.
uvx [email protected] format  # Format all files in the current directory.

Or install Ruff with uv (recommended), pip, or pipx:

# With uv.
uv tool install ruff@latest  # Install Ruff globally.
uv add --dev ruff            # Or add Ruff to your project.

# With pip.
pip install ruff

# With pipx.
pipx install ruff

This is the beginning of the README. Read the rest at the original. Read the full README ↗