An extremely fast Python linter and code formatter, written in Rust.
Linting the CPython codebase from scratch.
- ⚡️ 10-100x faster than existing linters (like Flake8) and formatters (like Black)
- 🐍 Installable via
- 🤝 Python 3.12 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 700 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 is extremely actively developed and used in major open-source projects like:
...and many more.
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.
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.
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.
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.
This is just ridiculously fast...
Table of Contents
For more, see the documentation.
For more, see the documentation.
Ruff is available as
ruff on PyPI:
pip install ruff
To run Ruff as a linter, try any of the following:
ruff check . # Lint all files in the current directory (and any subdirectories). ruff check path/to/code/ # Lint all files in `/path/to/code` (and any subdirectories). ruff check path/to/code/*.py # Lint all `.py` files in `/path/to/code`. ruff check path/to/code/to/file.py # Lint `file.py`. ruff check @arguments.txt # Lint using an input file, treating its contents as newline-delimited command-line arguments.
Or, to run Ruff as a formatter:
ruff format . # Format all files in the current directory (and any subdirectories). ruff format path/to/code/ # Format all files in `/path/to/code` (and any subdirectories). ruff format path/to/code/*.py # Format all `.py` files in `/path/to/code`. ruff format path/to/code/to/file.py # Format `file.py`. ruff format @arguments.txt # Format using an input file, treating its contents as newline-delimited command-line arguments.
- repo: https://github.com/astral-sh/ruff-pre-commit # Ruff version. rev: v0.1.6 hooks: # Run the linter. - id: ruff args: [ --fix ] # Run the formatter. - id: ruff-format
name: Ruff on: [ push, pull_request ] jobs: ruff: runs-on: ubuntu-latest steps: - uses: actions/checkout@v3 - uses: chartboost/ruff-action@v1
If left unspecified, Ruff's default configuration is equivalent to:
[tool.ruff] # Exclude a variety of commonly ignored directories. exclude = [ ".bzr", ".direnv", ".eggs", ".git", ".git-rewrite", ".hg", ".mypy_cache", ".nox", ".pants.d", ".pytype", ".ruff_cache", ".svn", ".tox", ".venv", "__pypackages__", "_build", "buck-out", "build", "dist", "node_modules", "venv", ] # Same as Black. line-length = 88 indent-width = 4 # Assume Python 3.8 target-version = "py38" [tool.ruff.lint] # Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`) codes by default. select = ["E4", "E7", "E9", "F"] ignore =  # Allow fix for all enabled rules (when `--fix`) is provided. fixable = ["ALL"] unfixable =  # Allow unused variables when underscore-prefixed. dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$" [tool.ruff.format] # Like Black, use double quotes for strings. quote-style = "double" # Like Black, indent with spaces, rather than tabs. indent-style = "space" # Like Black, respect magic trailing commas. skip-magic-trailing-comma = false # Like Black, automatically detect the appropriate line ending. line-ending = "auto"
Some configuration options can be provided via the command-line, such as those related to rule enablement and disablement, file discovery, and logging level:
ruff check path/to/code/ --select F401 --select F403 --quiet
ruff help for more on Ruff's top-level commands, or
ruff help check and
ruff help format
for more on the linting and formatting commands, respectively.
Ruff supports over 700 lint rules, many of which are inspired by popular tools like Flake8, isort, pyupgrade, and others. Regardless of the rule's origin, Ruff re-implements every rule in Rust as a first-party feature.
By default, Ruff enables Flake8's
F rules, along with a subset of the
E rules, omitting any
stylistic rules that overlap with the use of a formatter, like
ruff format or
If you're just getting started with Ruff, the default rule set is a great place to start: it catches a wide variety of common errors (like unused imports) with zero configuration.
Beyond the defaults, Ruff re-implements some of the most popular Flake8 plugins and related code quality tools, including:
- flake8-bandit (#1646)
- flynt (#2102)
For a complete enumeration of the supported rules, see Rules.
Contributions are welcome and highly appreciated. To get started, check out the contributing guidelines.
You can also join us on Discord.
You can also ask for help on Discord.
In some cases, Ruff includes a "direct" Rust port of the corresponding tool. We're grateful to the maintainers of these tools for their work, and for all the value they've provided to the Python community.
Ruff's import resolver is based on the import resolution algorithm from Pyright.
Ruff is the beneficiary of a large number of contributors.
Ruff is released under the MIT license.
Who's Using Ruff?
Ruff is used by a number of major open-source projects and companies, including:
- Amazon (AWS SAM)
- Anthropic (Python SDK)
- Apache Airflow
- AstraZeneca (Magnus)
- Benchling (Refac)
- Cryptography (PyCA)
- Databricks (MLflow)
- Great Expectations
- Home Assistant
- Hugging Face (Transformers, Datasets, Diffusers)
- ING Bank (popmon, probatus)
- Matrix (Synapse)
- Meltano (Meltano CLI, Singer SDK)
- Microsoft (Semantic Kernel, ONNX Runtime, LightGBM)
- Modern Treasury (Python SDK)
- Mozilla (Firefox)
- Netflix (Dispatch)
- Prefect (Python SDK, Marvin)
- Scale AI (Launch SDK)
- Snowflake (SnowCLI)
- Stable Baselines3
- The Algorithms
- WordPress (Openverse)
- build (PyPA)
- cibuildwheel (PyPA)
Show Your Support
If you're using Ruff, consider adding the Ruff badge to project's
.. image:: https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json :target: https://github.com/astral-sh/ruff :alt: Ruff
...or, as HTML:
<a href="https://github.com/astral-sh/ruff"><img src="https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json" alt="Ruff" style="max-width:100%;"></a>