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

ty is in active development, and we're working hard to make it stable and feature-complete.

uv tool install ty

Type check a Python file or project:

ty check myfile.py
ty check my_project/

Start the language server for IDE integration:

ty server

For detailed information about command-line options, see the CLI documentation.

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

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.

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.