ty

An extremely fast Python type checker and language server, written in Rust.

Shows a bar chart with benchmark results.

Type checking the home-assistant project without caching.

ty is backed by Astral, the creators of uv and Ruff.

Highlights

10x - 100x faster than mypy and Pyright
Comprehensive diagnostics with rich contextual information
Configurable rule levels, per-file overrides, suppression comments, and first-class project support
Designed for adoption, with support for redeclarations and partially typed code
Language server with code navigation, completions, code actions, auto-import, inlay hints, on-hover help, etc.
Fine-grained incremental analysis designed for fast updates when editing files in an IDE
Editor integrations for VS Code, PyCharm, Neovim and more
Advanced typing features like first-class intersection types, advanced type narrowing, and sophisticated reachability analysis

Getting started

Run ty with uvx to get started quickly:

uvx ty check

Or, check out the ty playground to try it out in your browser.

To learn more about using ty, see the documentation.

Installation

To install ty, see the installation documentation.

To add the ty language server to your editor, see the editor integration guide.

Getting help

If you have questions or want to report a bug, please open an issue in this repository.

You may also join our Discord server.

Contributing

Development of this project takes place in the Ruff repository at this time. Please open pull requests there for changes to anything in the ruff submodule (which includes all of the Rust source code).

See the contributing guide for more details.

FAQ

Why is ty doing _____?

See our typing FAQ.

How do you pronounce ty?

It’s pronounced as “tee - why” (/tiː waɪ/)

How should I stylize ty?

Just “ty”, please.

License

ty is licensed under the MIT license (LICENSE or https://opensource.org/licenses/MIT).

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in ty by you, as defined in the MIT license, shall be licensed as above, without any additional terms or conditions.