Letta: what it remembers, who owns it, and what it costs
thecontinuitylayer.com/memory-systems/lettaA platform for stateful agents with editable memory blocks, archival memory and portable Agent Files, run as Letta Cloud or a self-hosted server.
- 1Yes
Is Letta open source?
Yes, by Letta (formerly MemGPT)'s own page.
Both the letta and letta-code repositories are Apache-2.0; the README says active development is in letta-code.
Yes means: The core is under an open-source license.
- 2Yes
Can you run Letta yourself?
Yes, by Letta (formerly MemGPT)'s own page.
A self-hosted server is documented, with Docker, Docker Compose, Railway and Fly.io configurations.
Yes means: It runs on your own machine or server.
- 3Partly
Can you take your memory out of Letta?
Partly, by Letta (formerly MemGPT)'s own page.
An Agent File export contains the state needed to recreate the same agent, including memory blocks and message history; archival passages are marked as planned and secrets are exported empty.
Yes means: An export, or the data sits in a standard store you own.
- 4Yes
Does Letta work with more than one model provider?
Yes, by Letta (formerly MemGPT)'s own page.
The API supports the major providers, including Anthropic, OpenAI, Google, Azure, AWS Bedrock, OpenRouter and Ollama; agents keep their memory when the model is switched.
Yes means: It is not tied to one provider's models.
- 5Yes
Is there a hosted Letta?
Yes, by Letta (formerly MemGPT)'s own page.
Letta Cloud keeps an agent's memory, identity and conversations available across machines and is the default.
Yes means: A cloud or managed option exists.
- 6Yes
Does Letta have a free tier, and what is the entry price?
Yes, by Letta (formerly MemGPT)'s own page.
Free at $0 with your own keys and limited agents; Pro at $20 a month; a usage-based Developer plan; Enterprise custom.
Yes means: A free tier exists and the entry paid price is published.
- 7Partly
Does Letta scope memory per user and per session?
Partly, by Letta (formerly MemGPT)'s own page.
Memory belongs to an agent; shared blocks can attach to several agents, and a documented pattern attaches a user-preferences block across agents. Per-user scoping is a pattern, not a first-class store.
Yes means: Both per-user and per-session or per-agent memory are supported.
- 8Partly
Can you delete a user's memories from Letta?
Partly, by Letta (formerly MemGPT)'s own page.
A single archival passage can be deleted and blocks can be detached or overwritten; there is no documented delete-everything-for-a-user call because memory is agent-scoped.
Yes means: A documented way to delete everything for one user.
What these grades say about continuity, and what they do not.
Every grade on this site is read from the maker's own pages. The Continuity Framework asks five things of any system that carries state: that it carry, govern, evolve, prove and forget. These tests reach carry, govern and forget; they do not reach evolve or prove, which no maker's page documents in a gradeable way. A high letter is a good memory system, not a continuity layer.
- M1 Open sourceCarry
- Open source means the memory engine can outlive the vendor; the state is not hostage to a contract.
- M2 Self-hostCarry
- Self-hosting puts the store under the owner's control, which is the precondition for every other obligation.
- M3 ExportCarry
- An export is question C3: can the state leave in a form another system reads? A standard store you own answers it; a proprietary dump only partly.
- M4 Any modelCarry
- Working with more than one model provider is question C2: the memory, not the model, holds the state.
- M7 ScopingGovern
- Scoping per user, agent and session is question G2: who may read and write each item. It is the floor of governance, not the ceiling.
- M8 DeleteForget
- A documented delete for one user is rung 5 of the erasure ladder: the record leaves the store. Derived memories, the index and backups are not covered unless the maker says so. Rung 5 of the erasure ladder: delete the record.
License as stated: Apache-2.0. Every grade above is read from Letta (formerly MemGPT)'s own page on the day shown. If a page has changed, tell us.