JSON to Python Dataclass Generator

It reads a JSON sample and generates matching Python dataclasses, inferring the type of every field and adding the dataclasses and typing imports so you can paste the result straight into your code.

Each nested object becomes its own @dataclass, named in PascalCase from its key and defined before the class that references it. Lists infer their element type as List[T], a list of objects gets a generated class, and lists with mixed values become List[Union[...]].

Strings become str, whole numbers become int, decimals become float, and booleans become bool. A null value becomes Optional[Any] with a None default. JSON has no separate integer type, so a value like 36 maps to int while 1.5 maps to float.

Keys are converted to snake_case, so firstName becomes first_name. Fields that default to None are listed after the required fields because Python forbids a non-default field after a default one, which keeps the generated dataclass valid.

No. Parsing and code generation run entirely in your browser, so your data never leaves your machine.

The tool needs valid JSON with an object at the top level. Invalid syntax or a top-level array, string or number returns an error message instead of classes.