tox vs uv

tox is a free, open-source command-line tool for creating virtual environments, checking package builds and installations across different environments, and running tests in them. It can orchestrate test runners, linters, formatters, documentation generators, and build or publishing tools. As a continuous-integration frontend, tox combines CI workflows with shell-based testing and reduces boilerplate. Configuration can be stored in tox.toml, tox.ini, pyproject.toml, or toxfile.py. By default, it removes host environment variables unless allowed through pass_env and adjusts PATH so commands use the active environment. The command-line tool requires Python 3.10 or higher. Installation guidance covers pipx, uv, and pip, with apt and brew package-manager routes also documented. Plugins include tox-gh-actions for GitHub Actions, tox-uv for faster package installation, and tox-gh for enhanced GitHub integration. It runs on Linux, macOS, and Windows and is maintained as a volunteer open-source project.

uv is a Python package and project manager for Linux, macOS, and Windows. Written in Rust, it manages dependencies and environments, with lockfiles and workspaces, and can install, list, pin, or uninstall Python versions. It also runs scripts with dependencies and runs or installs command-line tools from Python packages. Its pip-compatible interface is intended to cover work done by tools such as pip, pip-tools, pipx, poetry, pyenv, twine, and virtualenv, though its commands do not exactly match those tools. The documentation describes uv as 10–100x faster than pip. It supports source distributions, wheels, requirements.txt, and pylock.toml, as well as offline installation and private registry authentication. For package selection, its default first-index strategy limits candidates to the first index where a package is found. Credentials are not stored in uv.lock, but uv currently stores them in a plaintext file; native system secret storage is an experimental preview. The free plan is free.