Python Type Checker Comparison: Typing Spec Conformance

When you write typed Python, you expect your type checker to follow the rules of the language. But how closely do today's type checkers actually follow the Python typing specification? In this post, we look at what typing spec conformance means, how different type checkers compare, and what the conformance numbers don't tell you.

https://pyrefly.org/blog/typing-conformance-comparison/

Python Type Checker Comparison: Typing Spec Conformance | Pyrefly

Learn what it means to conform to the Python typing spec, why it matters, and the conformance status of each type checker including Pyrefly, Ty, Pyright and Mypy.