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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 Review 2026 — Open-Source AI Agents with Long-Term Memory

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

Pros

    Cons

      Latest updates

      • Release v0.34.42 (v0.34.42)
      • Release v0.34.41 (v0.34.41)

        Exposes managed app ports in the sandbox.

      • Release v0.34.40 (v0.34.40)

        Rotates ChatGPT plans away from model_not_found errors and keeps attached-repository skills when repository fetching fails.

      • Release v0.34.39 (v0.34.39)

        Allows agent messages to address a conversation by ID alone and attaches recovery consumers to live duplicates.

      • Release v0.34.38 (v0.34.38)

        Streams subagent progress into task output files and logs every subagent task as JSONL, including remote workers.

      Capabilities

      • Agent that edits files — “Dynamic workflows invokes agents programmatically to compare plans across models, cross-check research, and migrate files in isolated Cloud sandboxes.” source
      • Command line — “Install in your terminal (requires Node.js 18+):” source
      • Choice of models — “Model-agnostic, managed agents” source
      • Self-hosted — “The same SDK interface to interact with stateful agents works against Letta Cloud, a self-hosted App Server, or entirely on your machine:” source
      • Official SDKs — “Today, we are launching the Letta Agents SDK, a TypeScript library for building with stateful agents.” source
      • Builds agents and workflows — “You can use the Agents SDK to create multi-agent and multi-user applications, for dynamic orchestration of agents, or to build custom interfaces on top of Letta agents.” source

      Get it

      Pricing

      Starting price
      $20/mo
      Prices checked
      2026-10-25

      Free

      Free

      • Limited agents
      • Limited usage of Letta Auto
      • Bring your own API keys and external coding plans

      Pro

      • $20 /month
      • Letta Auto weekly + monthly quota
      • Pay-as-you-go overage
      • Up to 20 stateful agents

      API Plan

      • $20 /month
      • Unlimited agents
      • API key authentication
      • Pay-as-you-go LLM usage

      Teams Pro

      • $20 /seat/month
      • Add teammates to your organization
      • Letta Auto weekly + monthly quota
      • Share agents and set access control

      Enterprise

      Price on request

      • Volume-based pricing
      • Increased quotas
      • Role-based access control
      • SAML/OIDC SSO
      • Dedicated support
      Official website