JSON to Python Dataclass Generator

What Is JSON to Python Dataclass Generator?

JSON to Python Dataclass Generator is a free online tool that converts a JSON object into Python dataclasses or Pydantic BaseModel classes with full type hints. It is designed for Python developers who work with REST APIs or structured data and want to avoid writing class definitions and type annotations by hand.

How to Use JSON to Python Dataclass Generator

1. Paste your JSON into the left panel, or click Load Sample to see an example.
2. Choose between @dataclass (standard library) or Pydantic (BaseModel) output.
3. Set the root class name (defaults to Root).
4. The generated Python classes appear instantly in the right panel.
5. Click Copy to copy the result to your clipboard.

Features

• Generates Python dataclasses or Pydantic BaseModel classes
• Full type hints: str, int, float, bool, List[T], Optional[Any]
• Recursively handles nested objects as separate classes
• JSON keys automatically converted to snake_case
• Null fields mapped to Optional[Any] = None
• Import statements generated automatically
• Runs entirely in your browser — zero data uploaded

FAQ

What is the difference between dataclass and Pydantic output?

The @dataclass mode generates Python standard library dataclasses from the dataclasses module. The Pydantic mode generates classes that inherit from BaseModel, which adds runtime validation, serialization, and other features from the Pydantic library.

What Python types are generated from JSON values?

JSON strings become str, booleans become bool, integers become int, floats become float, arrays become List[T], objects become nested dataclasses or BaseModel classes, and null values become Optional[Any] with a default of None.

Are field names converted to snake_case?

Yes. JSON keys are automatically converted to snake_case, which follows Python naming conventions (PEP 8).

Is my JSON data sent to a server?

No. All conversion runs entirely in your browser. Your data never leaves your device.