OpenAI API
API access to GPT-4o, o1, and other OpenAI models including embeddings and image generation. The most widely used LLM API in production.
Letta
Letta (formerly MemGPT) is an open-source framework for building stateful AI agents with persistent, editable memory. Agents remember conversations across sessions, search their own memory, and update their knowledge over time — solving context window limitations.