MyPy
The longest-established static type checker in the Python ecosystem. It performs static analysis of Python code using type hints and is one of the type checkers officially recommended by the Python project.
Timeline (last 90 days)
MyPy has long been the default static type checker in the Python ecosystem, but it is slow and frequently produces results inconsistent with CI.
In speed tests, Pyrefly checked PyTorch in 3.7 seconds versus MyPy's 54.92 seconds (approximately 15× faster), checked NumPy in 20 seconds versus MyPy's 1 minute 49 seconds, and checked scikit-learn in approximately 1 second versus MyPy's approximately 6.3 seconds (approximately 6× faster).
All Facts (2)
MyPy has long been the default static type checker in the Python ecosystem, but it is slow and frequently produces results inconsistent with CI.
50%UnverifiedIn speed tests, Pyrefly checked PyTorch in 3.7 seconds versus MyPy's 54.92 seconds (approximately 15× faster), checked NumPy in 20 seconds versus MyPy's 1 minute 49 seconds, and checked scikit-learn in approximately 1 second versus MyPy's approximately 6.3 seconds (approximately 6× faster).
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