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.
Zep
Memory and session management platform for AI assistants. Automatically extracts facts, preferences, and entities from conversations and surfaces them as structured memory. Supports temporal reasoning — knowing what was discussed last week versus now.