FastAPI headers: read, validate and set them (and the underscore trap)
Read request headers in FastAPI with Header(), handle repeated headers, group them in a Pydantic model, require API keys and set response headers. All tested.
OpenAI Responses API vs Chat Completions: what changes in your code
Side-by-side Python for the Responses API and Chat Completions: inputs, output_text, state with previous_response_id, tools, structured output and streaming.