uv venv: Fast Virtual Environment Command Reference

Create a venv in a fraction of the time.

uv venv creates a virtual environment much faster than python -m venv and can fetch a managed Python version on demand. It is the usual first step in a uv-based CI job.

Common flags / usage

• uv venv -- create .venv with the default interpreter
• --python 3.12 -- pin a Python version (downloaded if absent)
• uv venv myenv -- name the environment directory
• follow with uv pip install or uv sync

Example

- uses: astral-sh/setup-uv@v5
- run: uv venv --python 3.12
- run: uv pip install -r requirements.txt

In CI

Pass --python to build the environment on an exact version; uv can download a managed interpreter if it is missing, removing a separate setup-python step. As with any venv, activation does not persist across steps -- target the env by path or with --python.

Key takeaways

• uv venv creates virtual environments far faster than python -m venv.
• --python pins (and can download) a specific interpreter.
• It replaces a separate setup-python step in many uv-based jobs.

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