ty is an extremely fast Python type checker and language server,
Introduction
The entire ty architecture is built around “incrementality”, enabling ty to selectively re-run only the necessary computations when a user (e.g.) edits a file or modifies an individual function. This makes live updates extremely fast in the context of an editor or long-lived process.
You can install ty today with:
uv tool install ty@latestCorrect, pragmatic, and ergonomic. With features like first-class intersection types, advanced type narrowing, and sophisticated reachability analysis, ty pushes forward the state of the art in Python type checking, providing more accurate feedback and avoiding assumptions about user intent that often lead to false positives.
ty goal is not only to build a faster type checker; it’s to build a better type checker, and one that balances correctness with a deep focus on the end-user experience.