FastAPI now (temporarily) supports both Pydantic v2 models and `pydantic.v1` models at the same time in the same app, to make it easier for any FastAPI apps still using Pydantic v1 to gradually but quickly **migrate to Pydantic v2**.
FastAPI now (temporarily) supports both Pydantic v2 models and `pydantic.v1` models at the same time in the same app, to make it easier for any FastAPI apps still using Pydantic v1 to gradually but quickly **migrate to Pydantic v2**.