Pyright

Pyright was created to address gaps in existing Python type checkers like mypy.

Speed

Pyright is typically 5x or more faster than mypy and other type checkers that are written in Python. It is meant for large Python source bases. It can run in a “watch” mode and performs fast incremental updates when files are modified.

No Dependency on Python Environment

Pyright is written in TypeScript and runs within node. It does not require a Python environment or imported third-party packages to be installed. This is especially useful when used with the VS Code editor, which uses node as its extension runtime.

Configurability

Pyright supports flexible configuration that provides granular control over settings. Different “execution environments” can be specified for different subsets of a source base. Each environment can specify different PYTHONPATH settings, python language version, and platform target.