tox
tox is a generic virtualenv management and test command line tool
Decision gist · record as of 2026-08-14
Yes. tox is a mature, actively maintained tool (release within the last day, 3920 GitHub stars) with no known vulnerabilities, low install friction, and permissive MIT licensing. It is the standard for Python package testing automation and is essential if you need to verify compatibility across Python versions or environments. Install it if you maintain a Python package or work on projects that require multi-environment testing.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or later; tox manages its own virtual environments for testing, so you need a working Python installation and pip.
- Low install friction with a pure-Python wheel distribution.
- Active maintenance with a release within the last day and steady repository activity.
License · maintenance · safety
MIT (permissive) — MIT license is permissive, allowing use in commercial and proprietary projects with minimal restrictions beyond attribution.
last release 2026-08-13 (1 days) · last repo commit 2026-08-13 · 3,920 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 36,933,262 downloads/mo, #731 on PyPI
Alternatives
Verify before relying
pip install tox
# Create tox.ini in your project root with test environments
# Then run:
tox- Whether tox can be used as a library in addition to a CLI tool, or is primarily a command-line utility.
- Support for testing frameworks beyond pytest (e.g., unittest, nose2) and what configuration is needed.
What it is and what it does
tox is a command-line tool that automates testing of Python packages across multiple Python versions, implementations, and dependency configurations. It creates isolated virtual environments, installs your package and its test dependencies into each one, and runs your test suite in parallel or sequentially. This is essential for verifying that a package works correctly under the conditions your users will encounter—different Python versions, different OS platforms, and different dependency versions.
The tool integrates with continuous integration systems and reduces boilerplate by letting you define test environments once in a configuration file (tox.ini or pyproject.toml) rather than duplicating test logic across CI scripts. It depends on virtualenv for environment isolation and includes support for plugins and custom test commands, making it flexible enough to work with pytest, unittest, or other test frameworks.
Use it for
- Verify a package installs and passes tests on Python 3.10, 3.11, 3.12, 3.13, 3.14, and 3.15 before release.
- Run linting, type checking, and test suites in separate isolated environments to catch environment-specific issues.
- Automate testing in CI/CD pipelines by replacing shell scripts with a single tox command.
- Test a package against multiple versions of a critical dependency to ensure compatibility.
- Manage test environments locally during development without manually creating and destroying virtualenvs.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
tox is a mature, actively maintained tool (release within the last day, 3920 GitHub stars) with no known vulnerabilities, low install friction, and permissive MIT licensing. It is the standard for Python package testing automation and is essential if you need to verify compatibility across Python versions or environments. Install it if you maintain a Python package or work on projects that require multi-environment testing.
Install
tox on PyPI
Before you install
Low install friction with a pure-Python wheel distribution. Active maintenance with a release within the last day and steady repository activity. Requires Python 3.10 or later.
Requires Python 3.10 or later; tox manages its own virtual environments for testing, so you need a working Python installation and pip.
License in practice
MIT license is permissive, allowing use in commercial and proprietary projects with minimal restrictions beyond attribution.
Quickstart
pip install tox
# Create tox.ini in your project root with test environments
# Then run:
toxVerify before relying
- Whether tox can be used as a library in addition to a CLI tool, or is primarily a command-line utility.
- Support for testing frameworks beyond pytest (e.g., unittest, nose2) and what configuration is needed.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 12 packagescachetoolscoloramafilelockpackagingplatformdirspluggypyproject-apipython-discoverytomli-wtomlityping-extensionsvirtualenv |
| Maintenance | Actively maintained 1 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 36,933,262 / month, #731 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableFramework :: toxIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: MacOS :: MacOS XOperating System :: Microsoft :: WindowsOperating System :: POSIXProgramming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.15Topic :: Software Development :: LibrariesTopic :: Software Development :: TestingTopic :: Utilities |
Evidence: tox-4.60.0-py3-none-any.whl
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See also nox · tox-uv · tox-uv-bare · riot · tox-gh-actions · behavex · tox-gh · pytest-flake8 · pytest-item-dict