Letta
Platform for stateful agents with advanced memory, personalization, and learning over time.
Letta overview
Letta is an open-source platform for building stateful agents that remember users, maintain memory blocks, and interact through APIs and SDKs.
Stateful agent model
Letta treats memory as part of the agent state rather than a loose prompt append.
That makes it easier to build agents that remain coherent across sessions.API and SDK surface
Letta provides APIs and client SDKs for integrating stateful agents into applications.
Product teams need stable interfaces, not just demos.Active open-source platform
The project has frequent releases and documentation around agents and memory.
Active maintenance matters for infrastructure that sits inside an application.When to use Letta
Personalized AI agents
Build assistants that retain a persona and user-specific memory blocks.
Stateful agent APIs
Expose memory-backed agents inside applications through a service interface.
Learning workflows
Experiment with agents that improve from ongoing interactions.
How it compares
Letta is broader than memory storage; it is closer to a platform for agents whose behavior depends on state.
Questions
What should I check before using Letta?
Test Letta with repeated sessions. Add facts, update them, ask for recall, inspect retrieval behavior, and verify deletion or scoping controls before storing sensitive user or project memory.
Is Letta open source?
Letta is listed with Apache-2.0 based on the official source links in this profile. Re-check the repository, model card, or docs before production use.
Who should evaluate Letta?
Letta is most worth evaluating for developers building personalized stateful agents.