FDE Times guide: wrap a client's model as a tested, documented FastAPI service in one session

FDE Times published a hands-on guide on October 21 aimed at a common on-site moment: a client's data scientist hands over a notebook model and asks whether the app team can call it. The guide argues the most convincing answer is a working /docs link the client can try the same day, and walks through building one with FastAPI, the open-source Python web framework.

Its example wraps a late-delivery prediction model behind a POST /predict endpoint with Pydantic request and response models. Because FastAPI builds on type hints and the OpenAPI and JSON Schema standards, the schema, the interactive Swagger UI page and /openapi.json come for free. Setting response_model also strips undeclared fields, which the guide uses to keep a customer phone number from leaking out of the API.

The guide then shows writing tests in the same session with FastAPI's TestClient and pytest, with no server to start, starting with an assertion that personal data never appears in a response. It also advises pinning the FastAPI version in client demos, since the project is still pre-1.0 (version 0.157.0 shipped on October 21).

For FDEs, the takeaway is practical: a typed contract, live docs and a privacy test are what turn a quick demo into something a client's engineers can trust and build on toward production.