Ty: A fast Python type checker and LSP
3 days ago
- #Python
- #Rust
- #Type Checking
- ty is a fast Python type checker and language server written in Rust.
- Beta release announced, now used in Astral's projects and recommended for production.
- Designed for performance, 10x-60x faster than mypy and Pyright without caching.
- Features include first-class intersection types, advanced type narrowing, and sophisticated reachability analysis.
- Built with an obsessive focus on performance, correctness, and ergonomics.
- Includes a best-in-class diagnostic system inspired by Rust's error messages.
- Supports VS Code, Cursor, and other editors via the Language Server Protocol.
- Future goals include stability, feature completion, and support for third-party libraries like Pydantic and Django.
- Long-term vision includes powering semantic capabilities across the Astral toolchain.
- Acknowledgements to contributors and teams that influenced ty's development.