JSON → Python Data Class Generator

JSON Sample:

Root Class Name:

Model Type:

dataclass

pydantic

attrs

Indent:

Detect Optional fields

Naming Style:

Include to_dict/from_dict

Whether you’re building API clients, data validation layers, or just want a clean object model, this generator transforms raw JSON into fully‑typed, nested Python classes in seconds. Choose between standard library dataclasses for simplicity, Pydantic BaseModels for runtime validation, or attrs classes for performance—then customize naming conventions, optional detection, and even add serialization helpers. No more boilerplate or tedious manual mapping.

Recursive Class Generation: Automatically creates a Python class for every nested JSON object, preserving your data hierarchy.
List Type Inference: Maps JSON arrays to List[T] by inspecting the first element’s type and adds default_factory=list so lists are never uninitialized.
Optional Field Detection: Wraps fields in Optional[T] when values may be null or missing, assigning = None defaults for Pydantic or dataclasses.
Default & Example Support: Honors JSON default or examples by embedding them as field defaults when provided.
Naming Styles: Convert JSON keys on‑the‑fly to snake_case, camelCase, or leave them as‑is to match your codebase style.
Serialization Methods: Injects to_dict and from_dict for one‑line conversion between class instances and raw dictionaries.
Multiple Paradigms: Generate idiomatic @dataclass, Pydantic’s BaseModel with Field validation, or @attr.s classes with auto‑attribs.
Indent Control: Choose compact (2 spaces) or readable (4 spaces) indentation to fit your project’s formatting rules.
Error Handling: Receive clear feedback if your JSON is invalid or not supported (e.g., empty root arrays).

Before:

{
    "user_id": 42,
    "active": true,
    "roles": ["admin","user"],
    "profile": {
      "email": "u@example.com",
      "score": null
    }
  }

After (pydantic, snake_case, optional, methods):


  from pydantic import BaseModel, Field
  from typing import List, Optional, Any
  
  class Profile(BaseModel):
      email: str
      score: Optional[Any] = None
  
  class AutoGenerated(BaseModel):
      user_id: int
      active: bool
      roles: List[str] = Field(default_factory=list)
      profile: Profile
  
      def to_dict(self) -> dict:
          return self.dict()
  
      @classmethod
      def from_dict(cls, data: dict) -> 'AutoGenerated':
          return cls(**data)

Use this tool to rapidly scaffold data models, automatically enforce type safety, and eliminate manual mapping errors. Ideal for generating client SDKs, setting up test fixtures, or migrating legacy JSON‑driven code to modern, maintainable Python classes—giving you confidence and saving hours of boilerplate work.

JSON → Python Data Class Generator

Before:

After (pydantic, snake_case, optional, methods):

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