Python Static Type Checkers

Pyright is a static type checker for Python designed to validate type hints and identify potential errors within large codebases. It functions as a command-line utility that integrates into local development environments and continuous integration pipelines to ensure code quality and consistency. The tool distinguishes itself through a high-performance analysis engine that utilizes incremental dependency graph analysis and persistent state caching to re-evaluate only the affected portions of a project. By implementing the Language Server Protocol, it provides real-time feedback, including err

This project is a high-performance static type checker and comprehensive development toolkit for Python. It functions as a core analysis engine that identifies type inconsistencies and enforces code correctness, while simultaneously providing a language server implementation to deliver real-time diagnostics and intelligence directly within development environments. The tool distinguishes itself through a parallelized execution engine that maximizes performance across large-scale codebases and monorepo structures. It supports gradual type adoption, allowing developers to integrate type checkin

Pyrefly is a static type checker for Python that operates as a language server, delivering real-time diagnostics, completions, and navigation in any editor supporting the Language Server Protocol. It also performs static tensor shape analysis, using symbolic dimension variables and arithmetic to verify shape consistency in deep learning models without runtime execution. Beyond core type checking, Pyrefly supports gradual adoption workflows: it can generate a baseline of known errors so only new issues are reported, migrate configuration from other type checkers, and automatically suppress exi