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Letta

★ 20k

Stateful agents with long-term memory (ex-MemGPT) — build assistants that actually remember users across sessions.

Letta does the job of OpenAI Assistants API and Manus, self-hosted. It is Apache-2.0-licensed, so you can do essentially what you like with it, and setting it up is an afternoon, not a weekend. OpenAI Assistants API bills $20 for it. 20k stars on GitHub.

Open-source replacement for OpenAI Assistants API, Manus.

Licence
Apache-2.0
Self-hosting
Medium
The paid one costs
$20
GitHub stars
20k
view the code →official site →

Is it actually a replacement?

We have not written a verdict on OpenAI Assistants API or Manus yet, so this page says what Letta is rather than judging what you would give up. When that product gets a page, this one will link to it.

Letta questions

Is Letta open source?

Yes — it is released under Apache-2.0.

Can I self-host Letta?

Yes — we rate it medium to self-host.

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