OpenAI Agents SDK
OpenAI's production-grade agent framework, successor to Swarm. Core abstraction is explicit handoffs between agents carrying full context. Built for reliable multi-agent pipelines with native OpenAI tool use, tracing, and guardrails.
OpenAI API
API access to GPT-5, GPT-5.5, o3/o4 reasoning models, and the Responses API; plus embeddings, image, audio, and Realtime endpoints. The most widely deployed LLM API in production.