Python Type Hint Generator

About this tool

Paste an untyped (or partially typed) function signature and get type hints inferred from each parameter's default value — times=1 becomes times: int = 1, verbose=False becomes verbose: bool = False, and so on. Parameters that already have a hint are left untouched.

Frequently asked questions

How are types inferred?

From the literal type of each default value: numbers become int/float, quoted text becomes str, True/False becomes bool, [...] becomes list, {...} becomes dict, and None becomes Optional[Any] (there's no way to know the "real" type from None alone).

What happens to parameters with no default value?

They're hinted as Any, since there's no literal to infer a type from — replace it with the real type once you know it.

Does this figure out the return type automatically?

No — inferring a return type requires analyzing the function body (what it actually returns), which this tool doesn't do. Enter one manually if you know it, or leave it blank to omit the return annotation.