Install & Compatibility
Where this runs
tested against v0.0.75 · pip install
no network on importno background threads
Install × environment matrix
Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux
muslpy 3.10–3.95 runs
installs and imports cleanly · install 0.0s · import 0.000s · 18.2MB
glibcpy 3.10–3.95 runs
installs and imports cleanly · install 2.0s · import 0.000s · 19MB
16MB installed
● package 16MB
Code
Verified usage
Verified import paths — ran on the pinned version, not inferred.
ty
✓ ty check my_file.py
ty is primarily a command-line interface (CLI) tool for static analysis, not a Python library intended for direct programmatic import and use within application code. Its core is written in Rust.
Save the code above as `main.py`. Then, run `ty check` from your terminal in the same directory. ty will analyze the file and report the type error. Ensure `ty` is installed or run with `uvx`.
import typing
def greet(name: str) -> str:
return "Hello, " + name
# Intentional type error for demonstration
result: int = greet("World")
ty --version
Debug
Known issues
breakingty is currently in 0.0.x versioning, meaning its API is not yet stable. Breaking changes, including changes to diagnostics and configuration formats, may occur between any two versions. Users should review release notes for each update.fixAlways consult the latest documentation and release notes before upgrading. Adjust configurations and suppression comments (`# ty: ignore`) as needed.
affects: <=0.0.28 (all 0.0.x versions)
gotchaAs a preview release, ty is not yet recommended for production use. It may have missing features, known issues, or unexpected behavior in certain complex scenarios. It's best suited for experimentation, personal projects, or integrating into development workflows for fast feedback.fixUse with caution in critical environments. Consider using more mature type checkers like MyPy or Pyright for production systems until ty reaches a stable 1.0 release.
affects: <=0.0.28
gotchaWhen both `ty.toml` and `pyproject.toml` files are present in the same directory, `ty.toml` takes precedence for configuration settings, and the `[tool.ty]` section in `pyproject.toml` will be ignored.fixStandardize on one configuration file (`pyproject.toml` under `[tool.ty]` or a standalone `ty.toml`) to avoid unexpected behavior. Be aware of this precedence rule when troubleshooting configuration issues.
affects: <=0.0.28
gotchaCorrect environment discovery is crucial for ty to find installed packages and resolve imports. If ty cannot find an active virtual environment or a `.venv` directory, it may fall back to system Python, leading to `unresolved-import` diagnostics for project dependencies.fixEnsure you run `ty check` from within an activated virtual environment or use `uv run ty check`. Alternatively, explicitly specify the Python interpreter path using the `--python /path/to/python` flag.
affects: <=0.0.28
breakingFrom version `0.0.25`, ty introduced support for `type:ignore[ty:code]` suppressions, aligning with `ruff`'s suppression mechanism. Older, general `# type: ignore` comments might behave differently or be less granular.fixAdopt the more specific `type:ignore[ty:CODE]` syntax where `CODE` refers to the specific diagnostic code (e.g., `ty:invalid-return-type`) for fine-grained suppression. Review existing `# type: ignore` comments and update them for clarity and specificity.
affects: >=0.0.25
Upgrade
Version history
0.0.75latest on PyPI · released Aug 26, 2026
Audit
Dependencies
pythonrequiredRequires Python 3.8 or newer to run.