As contributors to the CPython project, our shared responsibility is to collaborate constructively with other contributors, including core developers. This responsibility covers all forms of contribution, whether that’s submitting patches to the implementation or documentation, reviewing other peoples’ patches, triaging issues on the issue tracker, or discussing design and development ideas on the core communication channels.

Core developers accept key additional responsibilities around the ongoing management of the project:

  • core developers bear the additional responsibility of handling the consequences of accepting a change into the code base or documentation. That includes reverting or fixing it if it causes problems in the Buildbot fleet or someone spots a problem in post-commit review, as well as helping out the release manager in resolving any problems found during the pre-release testing cycle. While all contributors are free to help out with this part of the process, and it is most welcome when they do, the actual responsibility rests with the core developer that merged the change

  • core developers also bear the primary responsibility for deciding when changes proposed on the issue tracker should be escalated to the appropriate Discourse category for wider discussion, as well as suggesting the use of the Python Enhancement Proposal process to manage the design and justification of complex changes, or changes with a potentially significant impact on end users

As a result of the additional responsibilities they accept, core developers gain the privilege of being able to approve proposed changes, as well as being able to reject them as inappropriate. Core developers are also able to request that even already merged changes be escalated to Discourse for further discussion, and potentially even reverted prior to release.

Becoming a core developer isn’t a binary “all-or-nothing” status - CPython is a large project, and different core developers accept responsibility for making design and development decisions in different areas (as documented in the Experts index and Developer log).

Communication channels and bug notifications

Mailing lists have generally been replaced by the Discourse forum ( Refer to the Mailing lists and Discourse ( web forum) sections for more information.

If you want notification of new issues, you can use the appropriate GitHub notification settings for the python/cpython repository — follow the link and click on the Watch button to set your notification options.

Sign a contributor agreement

Submitting a contributor form for Python licenses any code you contribute to the Python Software Foundation. While you retain the copyright, giving the PSF the ability to license your code means it can be put under the PSF license so it can be legally distributed with Python.

This is a very important step! Hopefully you have already submitted a contributor agreement if you have been submitting patches. But if you have not done this yet, it is best to do this ASAP, probably before you even do your first commit so as to not forget. Also do not forget to enter your GitHub username into your details on the issue tracker.

Pull request merging

Once you have your commit privileges on GitHub you will be able to accept pull requests on GitHub. You should plan to continue to submit your own changes through pull requests as if you weren’t a core developer to benefit from various things such as automatic integration testing, but you can accept your own pull requests if you feel comfortable doing so.


As a core developer, there are certain things that are expected of you.

First and foremost, be a good person. This might sound melodramatic, but you are now a member of the Python project and thus represent the project and your fellow core developers whenever you discuss Python with anyone. We have a reputation for being a very nice group of people and we would like to keep it that way. Core developers responsibilities include following the PSF Code of Conduct.

Second, please be prompt in responding to questions. Many contributors to Python are volunteers so what little free time they can dedicate to Python should be spent being productive. If you have been asked to respond to an issue or answer a question and you put it off it ends up stalling other people’s work. It is completely acceptable to say you are too busy, but you need to say that instead of leaving people waiting for an answer. This also applies to anything you do on the issue tracker.

Third, please list what areas you want to be considered an expert in the Experts index. This allows triagers to direct issues to you which involve an area you are an expert in. But, as stated in the second point above, if you do not have the time to answer questions promptly then please remove yourself as needed from the file so that you will not be bothered in the future. Once again, we all understand how life gets in the way, so no one will be insulted if you remove yourself from the list.

Fourth, please consider whether or not you wish to add your name to the Motivations and affiliations list. Core contributor participation in the list helps the wider Python community to better appreciate the perspectives currently represented amongst the core development team, the Python Software Foundation to better assess the sustainability of current contributions to CPython core development, and also serves as a referral list for organisations seeking commercial Python support from the core development community.

And finally, enjoy yourself! Contributing to open source software should be fun (overall). If you find yourself no longer enjoying the work then either take a break or figure out what you need to do to make it enjoyable again.