Letta
An open-source AI agent platform with persistent memory. Run agents locally or on a self-hosted server, with desktop apps for macOS, Windows, and Linux.
Letta is an open-source platform for AI agents that retain memory across conversations and use experience to improve over time. Formerly called MemGPT, it's for people building or using assistants that need continuity beyond a single chat. Agents can run locally or on a self-hosted server.
Memory is central to its approach: an agent's identity, context, and capabilities can evolve as it works. Letta's research covers programmatic context management, memory versioning with Git, and reasoning about stored context during idle time. These approaches focus on how agents retain and learn from experience, rather than treating each conversation as a fresh start.
You can interact with agents through a terminal interface or desktop apps for macOS, Windows, and Linux. Letta also offers a browser service at chat.letta.com that works on mobile. The browser service is separate from the local and self-hosted runtime.
For agents that need to participate in existing conversations, Letta supports Slack, Telegram, Discord, and custom channels. Its App Server provides the runtime for local or self-hosted agents, and the current codebase also includes the terminal interface and the runtime used by the desktop and web apps.
The linked letta-ai/letta repository is licensed under Apache 2.0. The retired V1 API server remains available as historical source; active development lives in letta-ai/letta-code.
