id 12345678

To fix your FastAPI example, you would therefore probably do this: from dataclasses import dataclass from uuid import UUID from fastapi import FastAPI from pydantic import BaseModel, Field class ApiSchema(BaseModel): id: UUID = Field(alias="uuid") foo: str | None = None class Config: orm_mode = True @dataclass class ORMModel: id: int uuid: UUID foo: str = "bar" app = FastAPI() @app. single setneg go id login get . single setneg go id login