Letta
Framework for stateful agents with long-term memory (formerly MemGPT).
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About Letta
Letta is listed in our frameworks category and is aimed at builders. Framework for stateful agents with long-term memory (formerly MemGPT). Pricing, as the maker states it: Open source + paid cloud. Maturity: Mature. We last checked the official link on 2026-10-14.
What is Letta?
Letta (formerly MemGPT) is a framework for building stateful agents with memory that can learn and improve over time. Its current source lives in letta-ai/letta-code, which includes the agent harness, a terminal UI, an App Server, channels and the runtime behind its apps.
You can run agents locally or self-hosted via the App Server, and use them from a desktop app for macOS, Windows and Linux, chat.letta.com, Slack, Telegram, Discord or the Letta Agent SDK. A paid cloud is also offered.
Sources: the official README and our directory listing, checked 2026-10-18. Official site: letta.com.
Who is Letta for?
Developers who want agents with long-term memory that persist and improve across conversations.
Letta at a glance
- Open source: Yes (Apache License 2.0)
- GitHub: letta-ai/letta · 25,214 stars (as of Oct 21, 2026)
Key features
- Stateful agents with long-term memory
- Self-hosted App Server
- Desktop, web and chat-app channels
- Agent SDK
- Open source plus paid cloud
Letta pricing
- Free: $0/mo · limited agents
- Pro: $20/mo · weekly and monthly Letta Auto quota
Heavier use is billed as usage on top; team and enterprise plans are listed separately.
Source: official pricing page, checked Oct 18, 2026. Prices change; check the source before buying.
Letta FAQ
What is Letta?
Letta (formerly MemGPT) is a framework for building stateful agents with memory that can learn and improve over time. Its current source lives in letta-ai/letta-code, which includes the agent harness, a terminal UI, an App Server, channels and the runtime behind its apps.
Who is Letta for?
Developers who want agents with long-term memory that persist and improve across conversations.
Is Letta free?
Yes. Letta has a free option (Free), according to its pricing page (checked Oct 18, 2026).
How much does Letta cost?
As of Oct 18, 2026, Letta's official pricing page lists: Free: $0/mo; Pro: $20/mo. Heavier use is billed as usage on top; team and enterprise plans are listed separately.
Is Letta open source?
Yes. Letta is released under the Apache License 2.0, according to its GitHub repository.
What are alternatives to Letta?
Similar tools include LangGraph, BaseAI, tRPC-Agent-Go, A2A, Agent Squad and Koog.
Letta ratings and reviews
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Letta alternatives
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Agent Squad
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Koog
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