Letta
Open-source platform for stateful AI agents with persistent memory. Build, observe, and deploy agents via ADE, REST API, SDKs, and a desktop app. Connect tools via MCP; use any model; run self-hosted or on Letta Cloud.
At a Glance
Get started with Letta at no cost with 50 premium requests / month and 500 standard requests / month.
Engagement
Available On
Alternatives
Updated Feb 2026
About Letta
Letta is a platform for building stateful AI agents with transparent, persistent memory (rooted in the MemGPT research). It ships a developer-first Agent Development Environment (ADE) for designing, observing, and editing agent state in real time, plus a REST API and Python/TypeScript SDKs to deploy agents as microservices. Agents are model-agnostic, support custom tools, and can connect to external tool libraries through Model Context Protocol (MCP).
You can self-host from the open-source repo or use Letta Cloud to create, version, and operate agents at scale with templates, monitoring, and observability. A cross-platform Letta Desktop app is available for local development. The platform supports BYO LLM API keys, filesystem-backed knowledge, multi-agent patterns with shared memory, and portability via an agent file format.
Community Discussions
Be the first to start a conversation about Letta
Share your experience with Letta, ask questions, or help others learn from your insights.
Pricing
Free
Get started with Letta at no cost with 50 premium requests / month and 500 standard requests / month.
- 50 premium requests / month
- 500 standard requests / month
- 100 active agents
- 2 agent templates
- 1 GB storage
Pro
Professional plan with 500 premium requests / month and 5,000 standard requests / month for power users.
- 500 premium requests / month
- 5,000 standard requests / month
- 10,000 active agents
- 20 agent templates
- 10 GB storage
- Monitoring & observability (cloud)
Scale
Scale plan with 5,000 premium requests / month and 50,000 standard requests / month.
- 5,000 premium requests / month
- 50,000 standard requests / month
- 10,000,000 active agents
- 100 agent templates
- 100 GB storage
- Advanced ops & team workflows
Enterprise
Enterprise-grade solution with Custom quotas and private model deployments and SAML/OIDC SSO and dedicated support.
- Custom quotas and private model deployments
- SAML/OIDC SSO
- Role-based access control (RBAC)
- BYOC deployment options
- Dedicated support
Capabilities
Key Features
- Persistent agent memory with transparent context management
- Agent Development Environment (ADE) for live inspect/edit of state, tools, and prompts
- Agents exposed as REST endpoints with auth/identities
- Python and TypeScript SDKs
- Model-agnostic: use OpenAI, Anthropic, Gemini, local (Ollama/vLLM)
- MCP integration for external tools and data sources
- Custom tools with sandboxed execution (cloud) and local tools (self-hosted)
- Agent templates, versioning, and rollbacks
- Monitoring and observability for production agents
- Self-hosting via Docker/pip or fully-managed Letta Cloud
- Desktop app for Mac/Windows/Linux (local agents)
- Filesystem and sources for document/knowledge ingestion
- Multi-agent systems with shared or linked memory
- Sleep-time/background workflows and request controls (tool rules)
- Portability between open source and cloud via agent file
Integrations
Demo Video
