uv

uv is what pip should have been. An extremely fast Python package manager written in Rust that handles virtual environments, dependency resolution, and project management in one tool. Astral (the Ruff people) is quietly building Python's default toolchain, and uv is the centerpiece.

If you're starting any Python project — solo SaaS, API, ML pipeline — use uv. The speed difference (10-100x faster than pip) makes everything else feel broken. Poetry is the established alternative but noticeably slower. PDM is solid but has less momentum. There's no commercial equivalent worth paying for.

Best for every Python developer, period. The combination of speed, correctness, and unified tooling is unmatched. It replaces pip, pip-tools, virtualenv, and pyenv in one binary.

The catch: uv moves fast. Breaking changes between versions still happen, so pin your version in CI. And if you're deep in a Poetry monorepo, migration is a weekend project, not a one-liner. The ecosystem of plugins and integrations is growing but not yet as wide as Poetry's.