Generate Python Pydantic models from JSON
Paste a JSON sample and get Pydantic models for Python. Nested objects become their own classes, and keys that are not valid Python names get a clean name with an alias.
How to use the JSON to Python converter
- Paste JSON or drop a .json file on the editor.
- Pydantic classes appear on the right as you type.
- Name the top-level class, for example Order.
- Copy the code, or download it as models.py.
What you get
- One BaseModel class per nested object
- Optional fields as T | None = None
- camelCase and dashed keys renamed to snake_case with Field(alias=...)
- Lists typed as list[T]
About the JSON to Python converter
Ready for FastAPI and AI SDKs
Pydantic models validate incoming data and are what FastAPI and many AI SDKs use to describe structured output.
Safe names
Keys such as first-name, createdAt or class are turned into valid Python names, and an alias keeps reading and writing the original JSON key.
Frequently asked questions
- Which Python version does the output need?
- Python 3.10 or newer, because unions are written as int | None. Pydantic 2 is assumed.
- How are classes ordered?
- Nested classes come first, so every class is defined before it is used.
- Is my JSON uploaded?
- No. The models are generated in your browser.