Mypy News

Mypy 0.4.5 released

7 Oct 2016

Mypy 0.4.5 was released. This release adds support for mypy configuration files and Python 3.6 variable annotations and includes many other improvements and fixes. There is now also a Gitter chat room. Read the blog post to see what's changed.

- Jukka

Mypy 0.4.4 released

25 Aug 2016

Mypy 0.4.4 was released. This release adds support for async/await and NewType and includes many other improvements and fixes. Read the blog post to see what's changed.

- Jukka

Mypy 0.4.3 released

14 Jul 2016

Mypy 0.4.3 was released. This release adds support for experimental strict checking of optional types (enabled using the --strict-optional command line option) and includes many other improvements and fixes. Read the blog post to see what's changed.

- Jukka

Mypy 0.4.2 released

9 Jun 2016

Mypy 0.4.2 was released. This release focuses on bug fixes. It also adds support for Type[C]. Read the blog post to see what's changed.

- Jukka

Mypy 0.4 released

5 May 2016

Mypy 0.4 was released. It's focused on faster type checking, usability improvements and bug fixes. Read the blog post to see what's changed.

- Jukka

Mypy 0.3 released

19 Feb 2016

Mypy 0.3 was released. It's focused on Python 2 support and better PEP 484 compatibility, but it's much improved in general. Read the blog post to see what's changed. Note that the mypy GitHub repo was moved to a new URL (

- Jukka

Mypy 0.2 released

5 Apr 2015

Mypy 0.2 was released. It's focused on PEP 484 (Type Hinting) draft compatibility and more complete Python feature support. Blog post

- Jukka

Mypy and the PEP 484 (type hinting) draft

17 Jan 2015

Read my blog post about PEP 484 (Type Hinting) draft, which proposes adding a standard type annotation syntax strongly inspired by mypy to the upcoming Python 3.5 release.

- Jukka

Revamped documentation

23 Nov 2014

We've been converting mypy documentation to reStructuredText/Sphinx and improving it in the process (thanks to Ryan Gonzalez for the bulk of the work!). The new docs are now public and hosted on The source code is available on GitHub.

- Jukka

Mypy only type checks, it does not run programs

31 Aug 2014

Mypy no longer runs your programs, it just type checks them. Use a Python interpreter to run programs.

- Jukka

Moving forward again

24 Jul 2014

Mypy development is seeing progress, after a pause. Stay tuned for exciting news! And we're still looking for new contributors. Also updated the web site to reflect the current development focus: static type checking.

- Jukka

Mypy switches to Python-compatible syntax

2 Jul 2013

Mypy now has a Python-compatible syntax! The implementation is already self-hosting. Have a look at the rewritten Mypy Tutorial (formerly Mypy Overview), README and the code. Also updated the roadmap. See the related blog post.

- Jukka

PyCon Update: Python-compatible syntax for mypy?

15 Apr 2013

I wrote a blog post about my PyCon visit and a new, Python-compatible syntax idea. The short summary is that mypy may get a 100% Python-compatible syntax in the future! Also Python 2.x support, structural subtyping and real multiple inheritance are being planned.

- Jukka

Mypy at PyCon US 2013 (Santa Clara, CA)

13 Mar 2012

I will present a poster about mypy at PyCon US this weekend. If you are coming to PyCon, you are welcome to come for a chat.

- Jukka

Mypy Development Update

13 Mar 2012

A lot has happened in the mypy project in the last few months. I've written a blog post about the most interesting recent developments.

- Jukka

Wiki opened

14 Dec 2012

The mypy wiki is now open. It contains useful information for both users and mypy developers, and it is editable by all. Related blog post

- Jukka

Source code released

7 Dec 2012

Mypy source code is now available on GitHub. Fork it and give it a try! The current prototype supports a useful but somewhat limited subset of Python features (library support is still limited) and lets you type check programs and run them by translating to Python. As such there is no performance boost yet.

- Jukka

Mypy has a blog and a newsletter, and is on Twitter

4 Dec 2012

I set up a mypy status blog. From now on, all important mypy updates will be posted there. There's also an Atom feed (it has been requested by several people). You can follow mypy development on Twitter (@mypyproject). Finally, you can also subscribe to an email newsletter hosted at Google Groups.

- Jukka

Mypy is self-hosting + language changes

2 Dec 2012

The mypy implementation has been self-hosting for about two weeks now (on top of CPython)! We are happily eating our own dog food. The source release is Real Soon Now. The release is a bit late as we decided to make some changes and add new features just before the release.

- Jukka

Mypy at PyCon Finland

25 Oct 2012

I gave a talk on mypy at PyCon Finland. Slides are available.

- Jukka