Static type checker for Python

Speed

Pyright is a fast type checker meant for large Python source bases. It can run in a “watch” mode and performs fast incremental updates when files are modified.

Configurability

Pyright supports configuration files that provide granular control over settings. Different “execution environments” can be associated with subdirectories within a source base. Each environment can specify different module search paths, python language versions, and platform targets.

Type Checking Features

• PEP 484 type hints including generics
• PEP 526 syntax for variable annotations
• PEP 544 structural subtyping
• PEP 589 typed dictionaries
• Type inference for function return values, instance variables, class variables, and globals
• Smart type constraints that understand conditional code flow constructs like if/else statements

VS Code Integration

Pyright ships as both a command-line tool and a VS Code extension that provides many powerful features that help improve programming efficiency.

VS Code Language Features

The VS Code extension supports many time-saving language features including:

• Intelligent type completion of keywords, symbols, and import names appears when editing
• Import statements are automatically inserted when necessary for type completions
• Signature completion tips help when filling in arguments for a call
• Hover over symbols to provide type information and doc strings
• Find Definitions to quickly go to the location of a symbol’s definition
• Find References to find all references to a symbol within a code base
• Rename Symbol to rename all references to a symbol within a code base
• Find Symbols within the current document or within the entire workspace
• Organize Imports command for automatically ordering imports according to PEP8 rules
• Type stub generation for third-party libraries

Built-in Type Stubs

Pyright includes a recent copy of the stdlib type stubs from Typeshed. It can be configured to use another (perhaps more recent or modified) copy of the Typeshed type stubs. Of course, it also works with custom type stub files that are part of your project.

Command-line Tool or Visual Studio Code Extension

Pyright includes both a command-line tool and an extension for Visual Studio Code that implements the Language Server Protocol.

For rich Python editing and debugging capabilities with Visual Studio Code, be sure to also install the official Microsoft Python extension for Visual Studio Code as Pyright only provides syntax and type checking.

Installation

VS Code Extension

You can install the latest-published version of the Pyright VS Code extension directly from VS Code. Simply open the extensions panel and search for pyright.

Vim

For vim/neovim users, you can install coc-pyright, Pyright extension for coc.nvim.

Command-line

The latest version of the command-line tool can be installed with npm, which is part of node. If you don't have a recent version of node on your system, install that first from nodejs.org.

To install pyright globally: npm install -g pyright

On MacOS or Linux, sudo is required to install globally: sudo npm install -g pyright

Once installed, you can run the tool from the command line as follows: pyright <options>

To update to the latest version: sudo npm update -g pyright

Using Pyright with VS Code Python Extension

Pyright provides some features that overlap with functionality provided by the standard VS Code Python extension: “hover”, type completion, definitions, references, rename symbols, etc. You may see duplicate results if Pyright is installed alongside the Python extension. There is currently no way to disable this functionality in the Python extension. If you want to disable these features in Pyright, there is a setting to do so: pyright.disableLanguageServices.

Documentation

• Getting Started with Type Checking
• Command-line Options
• Configuration
• Settings
• Comments
• Import Resolution
• Type Stubs
• Commands
• Building & Debugging
• Pyright Internals

Limitations

Pyright currently provides support for Python 3.0 and newer. There is currently no plan to support older versions.

Community

Do you have questions about Pyright or Python type annotations in general? Post your questions in this gitter channel.

FAQ

Q: What is the difference between pyright and the Microsoft Python Visual Studio Code plugin?

A: Pyright is focused on type checking. The Python VS Code plugin is Microsoft’s officially-supported extension for VS Code and provides a diverse array of features including debugging, test case management, linter plugins, and more. Pyright can be used alongside the Microsoft Python extension.

Q: What is the long-term plan for Pyright?

A: Pyright is a side project with no dedicated team. There is no guarantee of continued development on the project. If you find it useful, feel free to use it and contribute to the code base.

Contributing

This project welcomes contributions and suggestions. 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 opencode@microsoft.com with any additional questions or comments.