Memory systems for AI agents: which ones you can own, run and leave
thecontinuitylayer.com/memory-systemsMem0, Zep, Letta, LangMem, Cognee, Supermemory and more, read from their own docs and graded on the same eight questions: open source, self-hostable, exportable, provider-agnostic, hosted option, free tier and price, per-user scoping, and deletion.
Most of the open-source memory layers can be run on your own machine with any model provider, and the clearest differences are in export and deletion: few document a way to take everything out or to delete everything for one user. The vendor platform features (Anthropic, OpenAI, Google) are hosted and tied to their own models. Every grade is read from the maker's own page on the day shown.
Every product, every test.
✓ yes, ½ partly, ✕ no, – the maker's pages do not say. A dash counts for nothing: a product gets credit only for what its own pages state, so a vague page never outranks a clear one. On the training test the colors flip, because no is the good answer there.
| Product | Open source | Self-host | Export | Any model | Hosted | Free tier | Scoping | Delete | Score |
|---|---|---|---|---|---|---|---|---|---|
| Mem0#1 · Mem0 | A7½/8 | ||||||||
| LangMem and LangGraph Store#2 · LangChain | A7½/8 | ||||||||
| MemOS#3 · MemTensor | A−7/8 | ||||||||
| Letta#4 · Letta (formerly MemGPT) | B+6½/8 | ||||||||
| Cognee#5 · Cognee | B+6½/8 | ||||||||
| Honcho#6 · Plastic Labs | B+6½/8 | ||||||||
| Zep Cloud#7 · Zep | B6/8 | ||||||||
| Supermemory#8 · Supermemory | B6/8 | ||||||||
| Memobase#9 · memodb-io | B−5½/8 | ||||||||
| Claude memory tool#10 · Anthropic | C4½/8 | ||||||||
| Graphiti#11 · Zep | C4½/8 | ||||||||
| Agent Framework memory#12 · Microsoft | C−4/8 | ||||||||
| Agent Engine Memory Bank#13 · Google Cloud | D3½/8 | ||||||||
| OpenAI conversation state#14 · OpenAI | D3/8 |
In score order, best first.
Mem0
#1 · Mem0A memory layer for AI agents: an open-source library and server, plus a hosted platform, that extracts, stores and retrieves memories per user, agent and session.
A7½/8On the 8 tests- Is Mem0 open source?Yes
- Can you run Mem0 yourself?Yes
- Can you take your memory out of Mem0?Yes
LangMem and LangGraph Store
#2 · LangChainLangGraph's Store (namespaced JSON documents in a database you choose) plus the LangMem toolkit that extracts and manages memories in it.
A7½/8On the 8 tests- Is LangMem and LangGraph Store open source?Yes
- Can you run LangMem and LangGraph Store yourself?Yes
- Can you take your memory out of LangMem and LangGraph Store?Yes
MemOS
#3 · MemTensorA self-described memory operating system for agents with composable memory cubes, hybrid retrieval and skill memory; an open-source server plus a cloud API.
A−7/8On the 8 tests- Is MemOS open source?Yes
- Can you run MemOS yourself?Yes
- Can you take your memory out of MemOS?Partly
Letta
#4 · Letta (formerly MemGPT)A platform for stateful agents with editable memory blocks, archival memory and portable Agent Files, run as Letta Cloud or a self-hosted server.
B+6½/8On the 8 tests- Is Letta open source?Yes
- Can you run Letta yourself?Yes
- Can you take your memory out of Letta?Partly
Cognee
#5 · CogneeAn open-source memory engine that turns documents and conversations into graph and vector memory with multi-user datasets, plus a usage-priced Cognee Cloud.
B+6½/8On the 8 tests- Is Cognee open source?Yes
- Can you run Cognee yourself?Yes
- Can you take your memory out of Cognee?Partly
Honcho
#6 · Plastic LabsAn open-source memory server for stateful agents built around workspaces, peers and sessions, with background reasoning that builds user models; also offered as Honcho Cloud.
B+6½/8On the 8 tests- Is Honcho open source?Yes
- Can you run Honcho yourself?Yes
- Can you take your memory out of Honcho?Partly
Zep Cloud
#7 · ZepA managed temporal knowledge-graph context layer for agents, with per-user graphs, threads and a context API, built on the open-source Graphiti engine.
B6/8On the 8 tests- Is Zep Cloud open source?Partly
- Can you run Zep Cloud yourself?Partly
- Can you take your memory out of Zep Cloud?Partly
Supermemory
#8 · SupermemoryA memory and context engine offered as a hosted API and as a local single-binary server, with container-tag scoping and automatic forgetting of contradicted facts.
B6/8On the 8 tests- Is Supermemory open source?Partly
- Can you run Supermemory yourself?Yes
- Can you take your memory out of Supermemory?Partly
Memobase
#9 · memodb-ioUser-profile memory for chatbots: per-user profiles and event memory, as a dockerized server or Memobase Cloud.
B−5½/8On the 8 tests- Is Memobase open source?Yes
- Can you run Memobase yourself?Yes
- Can you take your memory out of Memobase?Partly
Claude memory tool
#10 · AnthropicA client-side, file-based memory tool on the Claude Developer Platform: Claude issues view, create, edit and delete commands against a memory directory that your application stores.
C4½/8On the 8 tests- Is Claude memory tool open source?No
- Can you run Claude memory tool yourself?Partly
- Can you take your memory out of Claude memory tool?Yes
Graphiti
#11 · ZepAn open-source framework for building real-time temporal knowledge graphs for agents; the engine inside Zep, run on your own graph database.
C4½/8On the 8 tests- Is Graphiti open source?Yes
- Can you run Graphiti yourself?Yes
- Can you take your memory out of Graphiti?Yes
Agent Framework memory
#12 · MicrosoftThe open-source successor to Semantic Kernel's memory: context providers that run before and after each turn, in-memory history providers, and a managed Foundry memory provider.
C−4/8On the 8 tests- Is Agent Framework memory open source?Yes
- Can you run Agent Framework memory yourself?Yes
- Can you take your memory out of Agent Framework memory?Partly
Agent Engine Memory Bank
#13 · Google CloudA managed Google Cloud service that generates, consolidates and retrieves long-term user memories from agent sessions, keyed by a scope such as a user id.
D3½/8On the 8 tests- Is Agent Engine Memory Bank open source?No
- Can you run Agent Engine Memory Bank yourself?No
- Can you take your memory out of Agent Engine Memory Bank?Partly
OpenAI conversation state
#14 · OpenAIServer-side conversation state for the Responses API: stored responses chained together, with a 30-day default retention, and durable Conversation objects reusable across sessions.
D3/8On the 8 tests- Is OpenAI conversation state open source?No
- Can you run OpenAI conversation state yourself?No
- Can you take your memory out of OpenAI conversation state?Partly
8 questions, the same for every memory system.
- 1
Is a memory system open source?
Yes means: The core is under an open-source license.
- 2
Can you run a memory system yourself?
Yes means: It runs on your own machine or server.
- 3
Can you take your memory out of a memory system?
Yes means: An export, or the data sits in a standard store you own.
- 4
Does a memory system work with more than one model provider?
Yes means: It is not tied to one provider's models.
- 5
Is there a hosted a memory system?
Yes means: A cloud or managed option exists.
- 6
Does a memory system have a free tier, and what is the entry price?
Yes means: A free tier exists and the entry paid price is published.
- 7
Does a memory system scope memory per user and per session?
Yes means: Both per-user and per-session or per-agent memory are supported.
- 8
Can you delete a user's memories from a memory system?
Yes means: A documented way to delete everything for one user.
Every grade is read from the maker's own documentation or pricing page on the day shown, with the page linked on the product's page. Nothing is graded from a review, a blog or a test we ran; where we test a product ourselves the page will say so. If a page has changed, tell us.
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.
The short answers.
- Which AI memory systems are open source and self-hostable?
- Mem0, Graphiti, Letta, LangMem, Cognee, MemOS, Honcho, Memobase and Microsoft's Agent Framework state an open-source license and a self-hosted setup. Supermemory's SDKs are open but its server binary is not. Zep Cloud is hosted, built on the open-source Graphiti.
- Which memory systems let me delete everything for one user?
- Mem0, Zep, MemOS and Memobase document a delete-by-user call. Letta, LangMem, Cognee, Supermemory, Honcho and Google's Memory Bank document deletion of single items or sessions only. Each product page quotes the maker's line.
- Do these work with any model?
- Mem0, Graphiti, Letta, LangMem, Cognee, Supermemory and Honcho list several providers including open models through Ollama. The platform features from Anthropic, OpenAI and Google work with their own models.
Placement here is never for sale and no link on this page pays us. How links work on this site. The consumer assistants are graded the same way on the Scorecard.