tools
Letta Review 2026 — Open-Source AI Agents with Long-Term Memory
Letta (formerly MemGPT) is a free open-source framework for AI agents with persistent long-term memory. Build AI companions and assistants that never forget.
Letta provides a runtime, SDK, API, and desktop or terminal tools for building agents that retain identity, memory, skills, and conversations across sessions and machines. Agents can run locally, on a self-hosted server, or through Letta Cloud.
Developers use it for coding agents, personal assistants, multi-agent applications, and embedded AI coworkers. Letta is open source, but cloud use, model providers, API keys, and managed infrastructure may cost extra. No official public pricing page with tier prices was read.
Features
- Persistent agent identity, memory, conversations, and experience
- Git-backed memory repositories with versioned context
- Skills, tools, subagents, and scheduled tasks
- Run agents locally, remotely, or through Letta Cloud
- TypeScript Agents SDK for stateful applications
- Channels for Slack, Discord, Telegram, and custom interfaces
- Open-source agent harness and self-hosted App Server
Use cases
- Build coding agents that remember projects and past decisions
- Create personal assistants for email, files, scheduling, and research
- Embed persistent agents in web, mobile, or business applications
- Coordinate multiple agents across shared conversations and tasks
- Run AI coworkers in Slack, Discord, or other communication channels