The official third-party software repository for Python is the Python Package Index, commonly called PyPI.
PyPI is an online index where developers publish and discover distributable Python packages. It hosts source distributions, known as sdists, and wheels, which can include precompiled binary components. The repository stores package metadata, release histories, compatibility information, and installation files.
The Python Software Foundation operates PyPI, while pip commonly uses it as its default package source. A command such as pip install requests typically searches PyPI unless the user configures another index or mirror. PyPI is separate from Python's standard library: installing Python provides built-in modules, while PyPI supplies a much larger ecosystem of optional packages.
The repository launched in 2003 and is sometimes nicknamed the Cheese Shop, a reference to a Monty Python's Flying Circus sketch. Common mix-ups include npm, which serves JavaScript packages; CRAN, associated with R; and CPAN, associated with Perl.