tox
tox is a free, open-source command-line tool for managing virtual environments and checking package builds and installations across different environments.
What tox is
tox is a free, open-source command-line tool for managing virtual environments and checking package builds and installations across different environments. It can create isolated environments, invoke test runners, linters, formatters, documentation generators, and build or publishing tools, then run those commands in each environment. tox can front continuous-integration servers, combining CI workflows with shell-based testing and reducing boilerplate. Configuration may be stored in tox.toml, tox.ini, pyproject.toml, or toxfile.py. By default, host environment variables are removed unless passed through with pass_env, and PATH is adjusted for the active environment. The command-line tool requires Python 3.10 or newer. Installation guidance covers pipx, uv, pip, apt, and brew. Plugins include tox-gh-actions, tox-uv, and tox-gh. It runs on Linux, macOS, and Windows.
Good
- Manages isolated virtual environments
- Runs tests and development tools
- Supports multiple configuration file formats
- Integrates with GitHub Actions
- Free and open source
Watch out
- Requires Python 3.10 or higher
- Command-line workflow may need configuration files
- Project is volunteer-maintained
Who it suits
tox suits developers who need repeatable environment setup and package testing across operating systems. It is also useful for teams connecting test commands with continuous-integration workflows.
Verdict
tox brings environment orchestration, package checks, and CI integration into one open-source command-line tool. Its plugin and configuration options support varied development workflows across Linux, macOS, and Windows.
Plans and prices
From tox's own pricing page, checked 10 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| tox | Free | Open-source command-line tool |
The facts
Each one read from tox's own pages, with the date it was checked.
What it does
- CI use
- tox can act as a frontend to continuous integration servers, reducing boilerplate and combining CI and shell-based testing.checked 10 Oct 2026
- Configuration
- tox reads configuration from files including tox.toml, tox.ini, pyproject.toml, and toxfile.py.checked 10 Oct 2026
- Environment isolation
- By default, tox removes host environment variables unless allowed through pass_env and adjusts PATH so commands resolve inside the active environment.checked 10 Oct 2026
- Environment orchestration
- tox can set up environments and invoke test runners, linters, formatters, documentation generators, and build and publishing tools.checked 10 Oct 2026
- GitHub Actions integration
- The tox-gh-actions plugin integrates tox with GitHub Actions for CI workflows.checked 10 Oct 2026
- Installation options
- The installation guide recommends pipx or uv for installing tox in an isolated environment and also provides pip instructions.checked 10 Oct 2026
- Man page
- tox includes a compiled man page in its wheel, and package managers such as apt and brew install it in an appropriate system location.checked 10 Oct 2026
- Plugin ecosystem
- tox supports plugins, including tox-uv for faster package installation and tox-gh for enhanced GitHub integration across environments.checked 10 Oct 2026
- Purpose
- tox manages virtual environments, checks package builds and installations across different environments, and runs tests in those environments.checked 10 Oct 2026
- Python requirement
- The tox command-line tool requires Python 3.10 or higher.checked 10 Oct 2026
- Support
- The development guide describes tox as a volunteer-maintained open-source project and directs people with issues to the issue tracker.checked 10 Oct 2026
Where it runs
- CLI and platform evidence
- The development guide documents running tox from a source checkout on Linux and Windows; the installation guide also describes package-manager installation with apt and brew.checked 10 Oct 2026
