OpenAI Python SDK

The official Python client for OpenAI’s API — chat completions, embeddings, the Assistants API, streaming responses, and function/tool calling, all typed and with both sync and async clients built in. Most Python projects calling OpenAI’s models directly use this rather than hand-rolling HTTP requests against the REST API.

Since the SDK only wraps the API itself, it doesn’t handle prompt orchestration, agent logic, or chaining multiple calls — that’s the layer frameworks like LangChain or DSPy sit on top of, often using this SDK underneath for the actual model calls. See What Is the OpenAI Python Library? for the full picture, including how it fits alongside Instructor and Pydantic AI.