Static Type Checker for Python

Pyright is a full-featured, standards-based static type checker for Python. It is designed for high performance and can be used with large Python source bases.

Pyright includes both a command-line tool and an extension for Visual Studio Code.

Pyright Playground

Try Pyright in your browser using the Pyright Playground.

Documentation

Refer to the documentation for installation, configuration, and usage details.

Performance

The weekly type checker benchmark compares Pyright with other Python type checkers.

The Pyright release history tracks per-package execution time and peak memory across releases.

Environment variables

If Pyright fails to create a temporary directory (for example in remote/server environments where the OS temp directory doesn't exist or isn't writable), you can override the temp directory root:

• PYRIGHT_TMPDIR: Absolute path to a directory that Pyright can use for temporary files/directories. Pyright will create it if needed.

Pyright otherwise relies on the platform temp directory (for example TMPDIR, TMP, TEMP, or the OS default).

Community

Do you have questions about Pyright or Python type annotations in general? Post your questions in the discussion section.

If you would like to report a bug or request an enhancement, file a new issue in either the pyright or pylance-release issue tracker. In general, core type checking functionality is associated with Pyright while language service functionality is associated with Pylance, but the same contributors monitor both repos. For best results, provide the information requested in the issue template.

Contributing

This project welcomes contributions and suggestions. For feature and complex bug fix contributions, it is recommended that you first discuss the proposed change with Pyright’s maintainers before submitting the pull request. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.