This page is about development of the Python Package Index (formerly known as Cheeseshop):

Developing the Package Index


Currently, as of 2019-06-27, PyPI has undergone a complete rewrite from scratch, and as a result much of the information on this page is not up-to-date.

The development moved from Mercurial (Python) to Git (C, shell). License changed from BSD-3 to Apache 2.0. Project code named 'warehouse' can be downloaded from:

Testing Your Stuff Against PyPI

If you need to test stuff against PyPI (registration, uploading, API activities) then please use the alternative server,

TO-DO list

Meta-to-do: file the issues below that are still unresolved in the GitHub issue tracker, then remove this section. -- SumanaHarihareswara 2019-08-23 10:57:10

Something that's been requested, but needs much more thought and analysis to see whether it causes any problems: the ability to treat project names and versions as case-insensitive, while removing extraneous characters (as in pkg_resources.safe_name()) for purposes both of searching and determining name uniqueness when registering.


Not Going TO-DO


Previous PyPI version

The legacy version of PyPI is the code that was running on for many years, till mid-2018. This LWN article goes into the history. The information below should help you get around the code.

Legacy PyPI architecture and endpoints

PyPI is a WSGI application that can be executed standalone using python pypi.wsgi command if all requirements are met. pypi.wsgi contains usual WSGI wrapper code and delegates request processing to method from This method just opens DB and handles exceptions, actual request processing is done in WebUI.inner_run(). This method analyzes URL endpoint and executes appropriate handler. As of 2011-04, the rules to match endpoints to handlers are the following:



dump all package names on single html page



dump all links for a package in html list



save as above, but signed by server



display static page with a list of mirrors



display current server time


XML-RPC requests are detected by CONTENT_TYPE=text/xml variable in CGI environment and processed by rpc.RequestHandler().__call__(). List of XML-RPC "endpoints" is available on PyPIXmlRpc page.

Legacy PyPI Development Environment Hints

Removed (visible in page history) because developing and running legacy PyPI is deprecated. -- SumanaHarihareswara 2019-08-23 10:57:10

CheeseShopDev (last edited 2019-08-23 10:57:11 by SumanaHarihareswara)

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