ty
Fast Rust-based Python type checker and language server from Astral, makers of uv and Ruff.
Recommended as the type checker in an Astral toolchain alongside uv and Ruff,123 with some saying it fixed or improved Python type checking.45Complaints vary rather than converge:678 lenient gradual typing that can hide errors, a reported hang at full CPU with no verbose mode, and doubts that it is ahead of Pyrefly yet.91011
Why people recommend it
Astral toolchain fit · 3
Commenters like pairing it with uv and Ruff in one Astral, Rust-based setup.
“This newly-minted fanboy recommends you try out ty w/ uv & ruff!”
“recently ty. It's also from astral and it fixed type checking. You should check it out”
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“I immediately set up up ruff, ty, pytest, pre-commit hook”
Better type checking · 2
Some say it fixed or improved Python type checking.
“recently ty. It's also from astral and it fixed type checking. You should check it out”
“other than `uv` and `ty`, I don't feel a whole lot has improved in Python land”
Replacing MyPy/Pyrefly · 1
One commenter moved codebases from MyPy to Pyrefly and then to ty.
“This newly-minted fanboy recommends you try out ty w/ uv & ruff!”
Script support · 1
Support for scripts filled a need one commenter had built an extension to solve.
“It's cool to see ty support for scripts.”
Caveats and dissent
Gradual typing · 1
It models uncertain types instead of failing, so possible errors may go unreported.
“I don't actually like ty that much”
Hangs · 1
One user saw it hang partway through a check at 100% CPU, with no verbose mode to debug.
“Is shows me progressbar and "98/99 files" then hang.”
Maturity vs rivals · 2
Pyrefly looked further along on support for common libraries, and Pydantic support was still pending.
“For all I know zuban or ty could be the better choice.”
“it looks like first class support from Ty is slated for the stable release, we'd love to try it.”
Fragmented CLI · 1
Its integration with uv and Ruff feels inconsistent across commands.
Weaker inference · 1
One user finds PyCharm's built-in checker better at inference through class inheritance.
“I use ty with Zed.”
Often compared with
From the makers not counted in the ranking
“Yes, we love TypeForm! We plan to support it as soon as the PEP for it lands.”
Threads where it came up
- Bringing uv and ty together 4 mentions
- Announcing the Beta release of ty 3 mentions
- Are you expected to run five Python type-checkers now? 1 mention
- Learn PHP in 2026 (Yes, Really) 1 mention
- Notes on Starting to Use Django 1 mention
- Ask HN: What non-LLM tools have meaningfully improved your dev productivity? 1 mention
Data: ty.json. Quotes are verbatim; the verdict and theme labels are written by a model from these comments, and every clause links to its sources.
All comments 12
“I don't actually like ty that much”
“For all I know zuban or ty could be the better choice.”
“It's cool to see ty support for scripts.”
“Now, ty is integrated into uv”
“I use ty with Zed.”
“other than `uv` and `ty`, I don't feel a whole lot has improved in Python land”
“I immediately set up up ruff, ty, pytest, pre-commit hook”
“recently ty. It's also from astral and it fixed type checking. You should check it out”
“I'm really glad the article mentioned ty as I'm going to try that today.”
“Is shows me progressbar and "98/99 files" then hang.”
“it looks like first class support from Ty is slated for the stable release, we'd love to try it.”
“This newly-minted fanboy recommends you try out ty w/ uv & ruff!”