PyPI (Python Package Index)

The Python Package Index (PyPI) is the official third-party software repository for the Python programming language, analogous to npm for JavaScript or crates.io for Rust. Maintained by the Python Software Foundation and powered by the Warehouse project (a modern rewrite replacing the legacy legacy PyPI codebase), PyPI hosts over 600,000 packages as of 2026, with billions of downloads per month. Python developers use pip (the package installer) to install packages from PyPI, and twine to publish their own packages. Key features include: package distribution hosting (source distributions/sdists and binary distributions/wheels for multiple platforms and Python versions), project metadata (describing package name, version, author, license, dependencies, classifiers for Python version and platform compatibility, and project URLs), semantic versioning support, dependency specification (install_requires in setup.py or dependencies in pyproject.toml with version constraints), project pages and documentation (README rendering in Markdown, reStructuredText, or plain text, with auto-generated links to documentation and issue trackers), release files (multiple downloadable files per release including wheels for different platforms), search and browsing (searching by name, keyword, or classifier, browsing by topic and framework), trusted publishers (OIDC-based publishing from CI/CD pipelines without API tokens, integrating with GitHub Actions, GitLab CI, and Google Cloud), API tokens (for authenticated package uploads with project-scoped or account-scoped permissions), two-factor authentication (TOTP and recovery codes), package scoring (based on maintenance, popularity, and other signals), vulnerability data integration (PyPI Advisory Database linking packages to known CVEs), and integration with pip and other package managers (uv, Poetry, Pipenv, conda).