Rust's focus on great error messages has been such a strength. We want to bring that same level of quality and craft to Python. The type checker shouldn't just tell you what went wrong, but why and (if possible) how to fix it.

(We also plan to bring this same diagnostic system to Ruff.)

Welcomed our new baby boy to the world on Friday. Everyone's doing great. Life is good!

Today, we’re announcing the preview release of ty, an extremely fast type checker and language server for Python, written in Rust. In early testing, it's 10x, 50x, even 100x faster than existing type checkers. (We've seen >600x speed-ups over Mypy in some real-world projects.)

Like Ruff and uv, we're building this project in the open alongside a community of contributors -- over a thousand PRs in total across 30+ authors. So first: thank you to everyone that's contributed to ty over the past few months!

There's still a long way to go on this project, but I'm hugely excited about where we're going with this. Let's make Python typing even more awesome than it already is!

This preview release is a little more "raw" than tools we've announced in the past. It's a huge, complex project, and it'll take time for it to feel production-ready. But we're now at the point where we want to iterate closely with users as we build the rest of this thing :)

I'm really proud that pysource-codegen is so useful. I hope to find the time to continue working on it in the future. The speed is something that can be improved. I started this as a proof of concept without knowing if it would work at all. Runtime was not my main goal back

You can also support my work if you want. github.com/sponsors/15r10…

Small moment of pride for me: Ibraheem Ahmed decided to _return_ to Astral for another internship this year, following an epic run with us last summer. Last time, he helped ship uv; this time, he'll be working on ty (and Salsa, the incremental-computation framework).

The ty diagnostics are getting so good. If you reference a symbol or module that was defined in a more recent Python version, we tell you that, and also tell you where/why we inferred the supported Python version.

The ty weekly updates are getting so ridiculous. It's like: we implemented these three new core typing features, solved one critical design challenge, and made everything 20% faster.

Today, we're announcing our first hosted infrastructure product: pyx, a Python-native package registry. We think of pyx as an optimized backend for uv: it’s a package registry, but it also solves problems that go beyond the scope of a traditional "package registry".

pyx is not yet generally available -- we're a small team, iterating on the product with early partners. If you're interested in the future of Python, if these problems resonate with you, or even if you're just a fan of our work: get in touch today 👇👇👇 astral.sh/pyx

Astral (the VC-backed company behind the popular open source Python tools uv, ruff and ty) have unveiled the first hints at their business model today - a private package registry for companies that use Python My notes here: simonwillison.net/2025/Aug/13/py…

We've been using pyx at fal and honestly, it's been incredible. No more late nights debugging CUDA versions or PyTorch incompatibilities, it just manages it. Our ML engineers actually thanked me for bringing this one and saving them tens of hours😅

We're continuing our commitment to the Open Source Pledge this year, projecting another $44,000 in open source sponsorship from the Astral OSS Fund to maintainers / projects we respect, depend on, and learn from.

🐍 Python 3.14 is here! 🎉 ✨ Template strings (t-strings) 🚀 Free-threaded Python officially supported 🎨 Syntax highlighting in the REPL 📦 Zstandard compression in stdlib 🔍 Remote PDB debugging Full release notes: docs.python.org/3.14/whatsnew/…

This year, we managed to ship Python 3.14 support for uv and Ruff on the day of the stable release. A big lift from the whole team. We wrote up a guide on some of our favorite features from 3.14, and how they affect our tools.

As of Python 3.14, the free-threaded (or no-GIL) version of the Python interpreter is no longer considered experimental.