ty is an extremely fast Python type checker and language server written in Rust, 10x-100x faster than mypy and Pyright, built for large codebases and real-time IDE feedback.
- 0.0.93
- Published at
- 22h ago
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- Synced at
- 9h ago
Latest release
0.0.93Oct 28, 2026, 12:53 AMDownloads slow? Switch the source anytime above
README
Project Overview
ty is a Python type checker and language server from Astral, the creators of uv and Ruff. Written in Rust, it is 10x-100x faster than mypy and Pyright. It provides rich contextual diagnostics, configurable rule levels, and per-file overrides, designed for gradual adoption with support for redeclarations and partially typed code. Its language server adds code navigation, completions, auto-import, and fine-grained incremental analysis tuned for editing.
| Item | Value |
|---|---|
| Language | Rust |
| Target code | Python 3.10+ |
| Status | Beta |
| License | MIT |
Type checking at the speed of real-time editor feedback.
Key Features
- Extremely fast: 10x-100x faster than mypy and Pyright
- Rich diagnostics: detailed context makes issues easy to locate and understand
- Configurable rules: rule levels, per-file overrides, and suppression comments
- Adoption ready: supports redeclarations and partially typed code for legacy projects
- Language server: navigation, completions, code actions, auto-import, hover help
- Incremental analysis: fine-grained incremental updates make IDE edits instant
- Editor integrations: official support for VS Code, PyCharm, Neovim, and more
- Advanced typing: intersection types, advanced narrowing, and reachability analysis
Target Audience
- Python developers
- Large codebase maintainers
- Teams that care about type-checking speed
- Heavy IDE users
- Teams seeking mypy or Pyright alternatives
Quick Start
- Run a check directly with uvx
uvx ty check- Or install ty and run in your project directory
ty checkConnect the ty language server to VS Code or PyCharm per the installation guide
Try it in the browser via the official Playground
Core Advantages
- Leading speed: one to two orders of magnitude faster than mainstream checkers
- Adoption friendly: designed for real codebases that are not fully typed
- Great IDE experience: incremental analysis keeps editor feedback instant
System Requirements
| Item | Requirement |
|---|---|
| OS | Linux, macOS, Windows |
| Target language | Python 3.10 or later |
| Installation | PyPI needs Python 3.8+; standalone installer needs no Python |
Notes
- Beta status: no stable API yet; breaking changes may occur between any two versions
- Older targets: checking Python 3.7-3.9 targets may cause false results due to missing stubs
- Development: source development happens mainly in the ruff submodule of the Ruff repo
Release history
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