Also, the best approach was to use already existing standards.

So, before even starting to code **FastAPI**, I spent several months studying the specs for OpenAPI, JSON Schema, OAuth2, etc. Understanding their relationship, overlap, and differences.

## Design

Then I spent some time designing the developer "API" I wanted to have as a user (as a developer using FastAPI).

    ) -> Type[BaseModel]:
        field_params = {f.name: (f.field_info.annotation, f.field_info) for f in fields}
        BodyModel: Type[BaseModel] = create_model(model_name, **field_params)  # type: ignore[call-overload]
        return BodyModel

else:
    from fastapi.openapi.constants import REF_PREFIX as REF_PREFIX
    from pydantic import AnyUrl as Url  # noqa: F401
    from pydantic import (  # type: ignore[assignment]