tox-uv

What it is and what it does

tox-uv is a tox plugin that swaps out virtualenv and pip with uv, the Rust-based Python package manager, for all test environment operations. It works as a drop-in replacement: install it alongside tox, and subsequent tox runs automatically use uv for environment creation and dependency resolution. The plugin supports multiple tox environment types (standard, lock-file-based, PEP 723 inline scripts, PEP 517 packaging, and external builders) and integrates with uv.lock files for reproducible test environments.

The package comes in two distributions: tox-uv (recommended, includes a bundled uv binary for immediate use) and tox-uv-bare (plugin only, for containerized setups where uv is already installed). You inherit both uv's speed advantages and any of its limitations or bugs. Discovery of the uv binary follows a priority chain: TOX_UV_PATH environment variable, bundled binary, or system PATH. The plugin is actively maintained, supports Python 3.10 through 3.14, and carries no known security vulnerabilities.

Use it for:

• Speed up CI/CD pipelines by replacing pip with uv's faster dependency resolution in tox test matrices.
• Use uv.lock files in tox to ensure reproducible test environments across developers and CI runs.
• Run PEP 723 inline script metadata through tox with uv as the backend for dependency isolation.
• Containerize test environments with tox-uv-bare to avoid bundling duplicate uv binaries in Docker images.
• Test projects that rely on uv-specific features like tool.uv.sources without leaving the tox workflow.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

tox-uv replaces virtualenv and pip with uv in tox environments, accelerating test environment creation and dependency installation while maintaining tox's test orchestration interface.

Yes. tox-uv is production-stable (Development Status 5), actively maintained, has zero known vulnerabilities, and low install friction. Install it if you want faster test environments and are comfortable accepting uv's behavior (including any bugs) as a trade-off for speed. Use tox-uv-bare in containerized environments to avoid redundant binary downloads.

Install

tox-uv on PyPI

pip install tox-uv

uv add tox-uv

poetry add tox-uv

Installing tox-uv

Before you install

Low friction: pure Python wheel with only two runtime dependencies (tox-uv-bare and uv). Actively maintained with a release 24 days ago and 351 repository stars.

License in practice

MIT license permits unrestricted use, modification, and distribution in both open-source and commercial projects.

Quickstart

pip install tox-uv
uv tool install tox --with tox-uv
tox r -e py312

Requires tox to be installed; tox-uv acts as a plugin that modifies tox's behavior rather than functioning standalone.

Verify before relying

• Whether uv's known bugs or incompatibilities with specific package types affect your test suite beyond tox-uv's control.
• Performance gains relative to virtualenv+pip for your specific dependency graph and test count.

Package facts

Evidence: tox_uv-1.36.0-py3-none-any.whl

Keywords: environments, isolated, testing, virtual

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