Astral, the company that made Python packaging fast with uv and linting fast with Ruff, is now aiming at the last slow tool in the Python workflow: the type checker. Its new checker, ty, is written in Rust and runs consistently 10 to 60 times faster than mypy and Pyright, and after you edit a load-bearing file it recomputes diagnostics in single-digit milliseconds instead of seconds. It is in beta today with a stable release targeted for 2026, and it is trying to pull off the same trick uv did: make a tool so much faster that switching feels obvious.
- ty is a Rust-based Python type checker and language server from Astral, the team behind Ruff and uv.
- It is 10 to 60 times faster than mypy and Pyright without caching, and about 80 times faster than Pyright on incremental edits.
- It went to beta in December 2025, with a stable release planned for 2026 focused on Pydantic and Django support and typing-spec conformance.
- The pitch is a uv-style speed leap for the editor and CI, with advanced type narrowing and intersection types under the hood.
What problem does ty actually solve?
Slow feedback. Type checkers like mypy and Pyright are enormously useful, catching whole classes of bugs before code runs, but on a large codebase they are also the part of the workflow developers most often disable or ignore because they are too slow to sit in the tight edit-save loop. That is the exact friction Astral has built a company around removing. ty is written in Rust, designed for incremental recomputation, and doubles as a language server so your editor gets the same fast diagnostics as the command line. The design goal is not just a faster batch run in CI, it is type feedback that keeps up with your keystrokes, so the checker stops being a chore you run occasionally and becomes ambient.
RelatedCloudflare Buys VoidZero, the Company Behind Vite
How much faster is it, really?
Enough that the numbers change behavior. Without caching, Astral measures ty at consistently 10 to 60 times faster than both mypy and Pyright on the same projects. The more striking figure is incremental: after editing a load-bearing file in the PyTorch repository, ty recomputes diagnostics in about 4.7 milliseconds, roughly 80 times faster than Pyright's 386 milliseconds and hundreds of times faster than some competitors. That is the difference between a checker that feels instant and one you wait on. Speed at that scale is not a vanity metric, it is what lets a tool live inside the editor's live loop rather than getting relegated to a pre-commit hook, and it is the same lever that made uv spread through the ecosystem so quickly.
| Checker | ty | mypy | Pyright |
|---|---|---|---|
| Language | Rust | Python | TypeScript/Node |
| Relative speed | 10–60× faster | Baseline | Fast, but slower than ty |
| Incremental edit | ~4.7ms (PyTorch) | Slow | ~386ms |
| Built-in language server | Yes | Via add-ons | Yes |
| Maturity | Beta (stable 2026) | Mature | Mature |
Is it ready to replace mypy today?
Not on its own, and Astral is candid about that. ty is still on 0.0.x versioning with no stable API, breaking changes can land between any two releases, and the gap between beta and stable is explicitly about the unglamorous work: closing the long tail of the Python typing specification, hitting more than 60% conformance, and adding first-class support for the libraries most real projects live in, above all Pydantic and Django. The recommended pattern for now is to run ty alongside your existing checker, using it for fast editor feedback while keeping mypy or Pyright as the source of truth in CI, then re-evaluating as ty approaches its stable release. It is a tool to adopt gradually, not a rip-and-replace.
How did Astral get here?
- 2022Ruff launches. A Rust linter that folds in Flake8, isort and more, and quickly becomes a default.
- 2024uv arrives. A Rust package and project manager that makes pip-style workflows dramatically faster.
- Dec 16 2025ty enters beta. The type checker and language server open up, promising 10–60× speedups.
- 2026Targeted stable release. Focus on typing-spec conformance and native Pydantic and Django support.
- Library support. ty is only a serious mypy replacement once Pydantic and Django type cleanly. That work gates stable.
- Conformance score. Watch the typing-spec conformance number climb past 60% toward parity.
- Editor adoption. The VS Code extension and language-server quality will decide whether developers switch daily drivers.
- The Astral pattern. If ty spreads like uv did, mypy and Pyright feel real pressure for the first time in years.
Our take
ty is the most interesting thing happening in Python tooling because Astral has a proven playbook and is running it again. Ruff and uv both looked like optional speedups at first and ended up as defaults, because once a tool is an order of magnitude faster, the friction of not using it starts to feel absurd. Type checking is a harder target than linting or packaging, correctness matters more and the Python type system has a long, subtle tail, which is exactly why Astral is right to stay in beta and not overpromise. But the direction is clear. A type checker fast enough to run on every keystroke changes how people write typed Python, turning types from a CI gate into live guidance. If the stable release lands with clean Pydantic and Django support, ty will not just be faster than mypy and Pyright, it will quietly become the way most Python developers experience type checking.
- Officialty documentation Astral's docs, install and roadmap
- Sourceastral-sh/ty on GitHub the repository, releases and issue tracker
- BenchmarkAstral — introducing ty the speed claims and design goals in the team's words
Original analysis by GenZTech. Release status current as of July 2026. More at Astral.