uv

uv is one Python tool that replaces a pile of them. It installs Python itself, creates virtual environments, locks and installs packages, and runs scripts, covering what pip, pip-tools, pipx, poetry, pyenv, twine and virtualenv do separately. It's written in Rust, its own benchmarks put it 10-100x faster than pip, and it's free under MIT or Apache 2.0.

Setup is one line with Astral's installer script, or just pip install uv. uv pip mirrors pip and pip-tools, so teams can switch before learning uv add and uv lock. Commit uv.lock and everyone gets the same environment. No account, no server, no paid tier.

Solo, small teams and larger teams: free. Poetry and PDM still work; uv is faster.

The catch: uv is still pre-1.0 and minor releases break things (0.13 switched the default Python to 3.15 and tightened constraint files), so pin its version in CI. It has also patched several malicious-package bugs, most recently a Windows path traversal in 0.12.18. And the money changed: Astral agreed in March 2026 to join OpenAI's Codex team, and its paid registry, pyx, stopped taking signups. OpenAI pledged to keep the tools open source, and the license lets you fork if that changes.