ty
An extremely fast Python type checker, written in Rust.
Decision gist · record as of 2026-08-14
Yes, if you want a fast, actively maintained type checker with modern IDE support and are comfortable with beta software. The zero runtime dependencies and wide platform support make installation straightforward. The 0.0.x versioning means diagnostics may change between releases, so pin the version in production workflows. No known security vulnerabilities.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.8 or later; officially supports type checking Python 3.10+ code, though earlier versions can be selected.
- Medium install friction due to platform-specific wheels, but the package is actively maintained with a recent release and no runtime dependencies.
- The project is in beta (0.0.71 versioning) and backed by Astral, the team behind uv and Ruff.
License · maintenance · safety
permissive license (permissive) — Licensed under MIT (permissive), allowing free use, modification, and distribution with minimal restrictions.
last release 2026-08-13 (1 days) · last repo commit 2026-08-13 · 19,460 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 39,433,122 downloads/mo, #696 on PyPI
Alternatives
Verify before relying
pip install ty
ty check- Whether the 10x–100x speed claims versus mypy and Pyright are measured under comparable conditions and codebase sizes.
- Current coverage of Python typing features and which advanced features (intersection types, sophisticated reachability analysis) are production-ready in 0.0.71.
- Stability of diagnostics output across patch releases, given the 0.0.x versioning and beta status.
What it is and what it does
ty is a type checker for Python written in Rust and maintained by Astral. It analyzes Python code for type errors and provides a language server for IDE integration (VS Code, PyCharm, Neovim). The package has no runtime dependencies and is distributed as pre-built wheels for multiple platforms and architectures.
The tool is positioned as a faster alternative to mypy and Pyright, with support for gradual typing, per-file configuration overrides, suppression comments, and incremental analysis for editor responsiveness. It officially targets Python 3.10+ but can analyze code for earlier versions. The project is in beta (0.0.x versioning), meaning breaking changes to diagnostics and the API may occur between releases.
Use it for
- Run type checking on large Python projects as part of CI/CD pipelines where speed is a priority.
- Use as a language server in an IDE for real-time type diagnostics and code navigation while editing.
- Gradually adopt type hints in existing codebases with support for partially typed code and per-file rule configuration.
- Analyze Python 3.7–3.9 codebases using a modern type checker despite targeting older Python versions.
- Integrate type checking into development workflows where fast incremental feedback is needed.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you want a fast, actively maintained type checker with modern IDE support and are comfortable with beta software.
The zero runtime dependencies and wide platform support make installation straightforward. The 0.0.x versioning means diagnostics may change between releases, so pin the version in production workflows. No known security vulnerabilities.
Install
ty on PyPI
Before you install
Medium install friction due to platform-specific wheels, but the package is actively maintained with a recent release and no runtime dependencies. The project is in beta (0.0.71 versioning) and backed by Astral, the team behind uv and Ruff.
Requires Python 3.8 or later; officially supports type checking Python 3.10+ code, though earlier versions can be selected.
License in practice
Licensed under MIT (permissive), allowing free use, modification, and distribution with minimal restrictions.
Quickstart
pip install ty
ty checkVerify before relying
- Whether the 10x–100x speed claims versus mypy and Pyright are measured under comparable conditions and codebase sizes.
- Current coverage of Python typing features and which advanced features (intersection types, sophisticated reachability analysis) are production-ready in 0.0.71.
- Stability of diagnostics output across patch releases, given the 0.0.x versioning and beta status.
Package facts
| License | permissive license permissive |
| Python support | Supports the current Python release >=3.8 |
| Install friction | Medium. Platform-specific wheel |
| Runtime dependencies | None |
| Maintenance | Actively maintained 1 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 39,433,122 / month, #696 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaEnvironment :: ConsoleIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: PythonProgramming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Programming Language :: RustTopic :: Software Development :: LibrariesTopic :: Software Development :: Libraries :: Python ModulesTopic :: Software Development :: Quality AssuranceTopic :: Software Development :: Testing |
Evidence: ty-0.0.71-py3-none-linux_armv6l.whl; ty-0.0.71-py3-none-macosx_10_12_x86_64.whl; ty-0.0.71-py3-none-macosx_11_0_arm64.whl; ty-0.0.71-py3-none-manylinux_2_17_aarch64.manylinux2014_aarch64.whl; ty-0.0.71-py3-none-manylinux_2_17_armv7l.manylinux2014_armv7l.whl; ty-0.0.71-py3-none-manylinux_2_17_i686.manylinux2014_i686.whl; ty-0.0.71-py3-none-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl; ty-0.0.71-py3-none-manylinux_2_17_s390x.manylinux2014_s390x.whl; ty-0.0.71-py3-none-manylinux_2_17_x86_64.manylinux2014_x86_64.whl; ty-0.0.71-py3-none-manylinux_2_31_riscv64.whl; ty-0.0.71-py3-none-musllinux_1_2_aarch64.whl; ty-0.0.71-py3-none-musllinux_1_2_armv7l.whl; ty-0.0.71-py3-none-musllinux_1_2_i686.whl; ty-0.0.71-py3-none-musllinux_1_2_x86_64.whl; ty-0.0.71-py3-none-win32.whl; ty-0.0.71-py3-none-win_amd64.whl; ty-0.0.71-py3-none-win_arm64.whl
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