astral-sh/uv

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

Installation

Install uv with our standalone installers:

# On macOS and Linux.
curl -LsSf https://astral.sh/uv/install.sh | sh

# On Windows.
powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"

Or, from PyPI:

# With pip.
pip install uv

# Or pipx.
pipx install uv

If installed via the standalone installer, uv can update itself to the latest version:

uv self update

See the installation documentation for details and alternative installation methods.

Documentation

uv's documentation is available at docs.astral.sh/uv.

Additionally, the command line reference documentation can be viewed with uv help.

Features

Projects

uv manages project dependencies and environments, with support for lockfiles, workspaces, and more, similar to rye or poetry:

$ uv init example
Initialized project `example` at `/home/user/example`

$ cd example

$ uv add ruff
Creating virtual environment at: .venv
Resolved 2 packages in 170ms
   Built example @ file:///home/user/example
Prepared 2 packages in 627ms
Installed 2 packages in 1ms
 + example==0.1.0 (from file:///home/user/example)
 + ruff==0.5.0

$ uv run ruff check
All checks passed!

$ uv lock
Resolved 2 packages in 0.33ms

$ uv sync
Resolved 2 packages in 0.70ms
Checked 1 package in 0.02ms

See the project documentation to get started.

uv also supports building and publishing projects, even if they're not managed with uv. See the publish guide to learn more.

Scripts

uv manages dependencies and environments for single-file scripts.

Create a new script and add inline metadata declaring its dependencies:

$ echo 'import requests; print(requests.get("https://astral.sh"))' > example.py

$ uv add --script example.py requests
Updated `example.py`

Then, run the script in an isolated virtual environment:

$ uv run example.py
Reading inline script metadata from: example.py
Installed 5 packages in 12ms
<Response [200]>

See the scripts documentation to get started.

Tools

uv executes and installs command-line tools provided by Python packages, similar to pipx.

Run a tool in an ephemeral environment using uvx (an alias for uv tool run):

$ uvx pycowsay 'hello world!'
Resolved 1 package in 167ms
Installed 1 package in 9ms
 + pycowsay==0.0.0.2
  """

  ------------
< hello world! >
  ------------
   \   ^__^
    \  (oo)\_______
       (__)\       )\/\
           ||----w |
           ||     ||

Install a tool with uv tool install:

$ uv tool install ruff
Resolved 1 package in 6ms
Installed 1 package in 2ms
 + ruff==0.5.0
Installed 1 executable: ruff

$ ruff --version
ruff 0.5.0

See the tools documentation to get started.

Python versions

uv installs Python and allows quickly switching between versions.

Install multiple Python versions:

$ uv python install 3.12 3.13 3.14
Installed 3 versions in 972ms
 + cpython-3.12.12-macos-aarch64-none (python3.12)
 + cpython-3.13.9-macos-aarch64-none (python3.13)
 + cpython-3.14.0-macos-aarch64-none (python3.14)

Download Python versions as needed:

$ uv venv --python 3.12.0
Using Python 3.12.0
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate

$ uv run --python [email protected] -- python --version
Python 3.8.16 (a9dbdca6fc3286b0addd2240f11d97d8e8de187a, Dec 29 2022, 11:45:30)
[PyPy 7.3.11 with GCC Apple LLVM 13.1.6 (clang-1316.0.21.2.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>>

Use a specific Python version in the current directory:

$ uv python pin 3.11
Pinned `.python-version` to `3.11`

See the Python installation documentation to get started.

The pip interface

uv provides a drop-in replacement for common pip, pip-tools, and virtualenv commands.

uv extends their interfaces with advanced features, such as dependency version overrides, platform-independent resolutions, reproducible resolutions, alternative resolution strategies, and more.

Migrate to uv without changing your existing workflows — and experience a 10-100x speedup — with the uv pip interface.

Compile requirements into a platform-independent requirements file:

$ uv pip compile requirements.in \
   --universal \
   --output-file requirements.txt
Resolved 43 packages in 12ms

Create a virtual environment:

$ uv venv
Using Python 3.12.3
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate

Install the locked requirements:

$ uv pip sync requirements.txt
Resolved 43 packages in 11ms
Installed 43 packages in 208ms
 + babel==2.15.0
 + black==24.4.2
 + certifi==2024.7.4
 ...

See the pip interface documentation to get started.

Contributing

We are passionate about supporting contributors of all levels of experience and would love to see you get involved in the project. See the contributing guide to get started.

FAQ

How do you pronounce uv?

It's pronounced as "you - vee" (/juː viː/)

How should I stylize uv?

Just "uv", please. See the style guide for details.

What platforms does uv support?

See uv's platform support document.

Is uv ready for production?

Yes, uv is stable and widely used in production. See uv's versioning policy document for details.

Acknowledgements

uv's dependency resolver uses PubGrub under the hood. We're grateful to the PubGrub maintainers, especially Jacob Finkelman, for their support.

uv's Git implementation is based on Cargo.

Some of uv's optimizations are inspired by the great work we've seen in pnpm, Orogene, and Bun. We've also learned a lot from Nathaniel J. Smith's Posy and adapted its trampoline for Windows support.

License

uv is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in uv by you, as defined in the Apache-2.0 license, shall be dually licensed as above, without any additional terms or conditions.