Pyrefly

Pyrefly now works with Pylance in VS Code! The new Type Server Protocol (TSP) allows users to keep using Pylance in VS Code while powering type checking and other diagnostics with Pyrefly read the blog: pyrefly.org/blog/pyrefly...

If you've struggled with shape bugs in PyTorch, NumPy or JAX you can use Pyrefly shape checking to catch mismatches statically, before you run your code: www.youtube.com/watch?v=2dAB... Also if you're at #pytorchcon you can chat to Avik and Steven IRL: events.linuxfoundation.org/pytorch-conf...

🐍 Come find our Meta booth at @PyConTW! 👋 Our team is here to talk about: 🔥 Pyrefly, 🧵 Free-threaded Python, 🛟 Safer Lazy Imports, and More! #pycontw #pycontw2026 #Python #OpenSource #Pyrefly #FreeThreading

The Pyrefly team wants to hear from you! If you'd like to help make Pyrefly better and have a spare 10 mins to fill out this survey we would greatly appreciate it - whether you’re just getting started trying out Pyrefly or you’ve been here since the beginning: 📝 forms.gle/1ytEGVpsqokm...

The best open source tool for the job doesn't have to be built in-house. When evaluating Python type checkers, Google chose @pyrefly.org—originally built at Meta—and started contributing upstream alongside the community. Read our journey: goo.gle/pyrefly-at-g...

🐍 We're at @pybay.bsky.social! Come find the Meta booth and say hi 👋 Our team is here to talk about: 🔥 Pyrefly, 🧵 Free-threaded Python, 🛟 Safer Lazy Imports, and More! Can't make it? Find us on GitHub: github.com/facebook/pyrefly #PyBay2026 #Python #OpenSource #Pyrefly #FreeThreading

Tech with Tim has a new video out featuring Pyrefly 🎥 It covers the basics of getting started with type checking, including getting your agent to use Pyrefly www.youtube.com/watch?v=lFA-...

Your Friday side quest: whatsnewt, a terminal adventure through Python 3.15 where you solve puzzles by writing real code. Pyrefly checks your answers to the typing puzzles. Type checking is a game mechanic now. 🎮 pypi.org/project/what...

@napari.org reports its Pyrefly check at ~0.7s warm / 0.9s cold, versus ~15–25s cold in its previous mypy setup. Fast checks change habits: run it locally, fix the thing, move on. Compute left for science. Thanks for the great write-up on your experience! napari.org/island-dispa...

At PyTorch Conference North America 2026 (October 20–21 in San Jose, CA), Avik Chaudhuri from Meta will break down how PyreFly - a static type checker for Python - enables end-to-end static shape coverage for PyTorch models. Register for #PyTorchCon North America today: bit.ly/4qStJvL

✨ The Pyrefly type-checker now tracks Polars DataFrame schema 🏷️ Declare a schema using Annotated 📚 Enjoy clearer self-documenting code and avoid some schema-related issues before hitting prod 😇 The annotated schema will be ignored by other type-checkers so you won't get conflicts between them

Congratulations on JupyterHub 6.0 🎉 Notebooks aren’t a side quest to “real” Python—they’re where students, researchers, and data teams do real work. We’re excited to keep learning from the Jupyter community as we think about tooling that respects the notebook workflow.

The PSF Board is proud to share the final version of the PSF’s five-year strategic plan. Thanks to all who improved the plan by participating in the process, and we look forward to all we’ll accomplish together in the next five years. Read more on our blog:

New to Python types? Don’t start with “annotate everything.” Start with a number. `pyrefly coverage check` makes progress visible- including a public-API-only option. Type migrations need a progress bar, not a guilt trip. What would you type first? pyrefly.org/blog/why-typ...

Pyrefly 1.3 is here 🥳 Smarter checks, better Django, SQLAlchemy and PyTorch support, workspace-wide search, refactorings—and experimental JAX and NumPy shape checking. New to type checking? Kick the tires and let us know what you think! github.com/facebook/pyr...

Pyrefly 1.3.0-dev.4: better decorator navigation, inlay hints, cross-file call hierarchy, autocomplete, and tensor-shape typing. It’s a dev build: try it, report bugs, don’t staple it to production. github.com/facebook/pyr...

From Google’s Dev blog this week: run cheap, deterministic checks before calling the model. For Python, that’s a Pyrefly-sized job: let static analysis handle facts before spending tokens on vibes. developers.googleblog.com/4-engineerin...

Hello, Bluesky 👋 We’re Pyrefly: an open-source type checker and language server, fast enough for every keystroke and built for Python in the wild - from your first type hint to production. Expect typing puzzles, engineering notes, and well-typed snark. What should we dig into first? pyrefly.org