Vote to promote Jelle Zijlstra

Jelle’s been involved in Python-related projects for many years. Over the past year, I’ve seen increased interest by him to contribute to Python core and I think he is ready for his commit bit. In fact, I think this is past due.

His day job is at Quora where he, among other things, develops asynq, a mature asynchronous programming library with a focus on batching. Open source-wise, you might already know Jelle’s work through his contributions to:

  • python/cpython where he’s got over 30 landed pull requests,
  • python/mypy where he is a maintainer with over 70 landed pull requests,
  • python/typeshed which he maintains and stubbornly attempts to type-annotate the Internet with over 400 landed pull requests,
  • psf/black where he is a lead maintainer, overtaking me for closed issues in September 2021,
  • pycqa/flake8-pyi where he maintains a plugin for flake8 which lints typing stub files.

Jelle is smart, hard-working, well-spoken, inquisitive, and sensible. Among my many interactions with him, I can’t recall a single bad one. I’ve always been impressed by his combination of brilliance and humility.

While my list of his contributions above focuses on his coding output, you might see from his GitHub stats that 50% of his work is in fact in reviewing changes by others. He is an excellent and timely reviewer. This is something Jelle is explicitly interested in, which is terrific given our growing open PR backlog. Apart from that, as you can see from his area of expertise, Jelle will be focusing on maintaining and shepherding the implementation of new typing PEPs and reviewing other changes to this area of CPython.

In accord with PEP 13, I’ll close the poll a week from now (10:00pm CET, February 15th).

It is granted by receiving at least two-thirds positive votes in a core team vote that is open for one week and with no veto by the steering council.

  • Promote Jelle Zijlstra
  • Do not promote Jelle Zijlstra

0 voters


Yes! Jelle has impressed me from the first time he showed up in the mypy project. I have been mentoring him a bit so he can be confident as a core dev; but really, he was ready a long time ago.


Welcome on board, @Jelle!


Thanks everyone for your trust! I’m excited to help make CPython better.