Guide, updated Oct 16, 2026
Best memory layers for AI agents
Long-term memory layers so agents remember users and tasks. We list 5 memory and context layers, 3 open source. Summaries come from each vendor's own site and every link was checked on or before Oct 16, 2026.
Shortlist
All 5 at a glance
Alphabetical. Nothing in this guide is a paid placement.
| Tool | What it does | Open source | More |
|---|---|---|---|
| Cognee | Open-source agent memory platform built on graph and vector stores. | Yes | Alternatives |
| Letta | Platform for stateful agents that keep long-term memory. | Yes | Alternatives |
| Mem0 | Memory layer that lets agents learn from past interactions. | Yes | Alternatives |
| Supermemory | Memory and continual learning engine for agents. | No | Alternatives |
| Zep | Context layer that unifies business data, documents, and chats for agents. | No | Alternatives |
How to choose
What to check before you pick
- Memory model: vector search, a knowledge graph, or both, and how memories are updated or forgotten.
- Scope: per user, per agent or per organization memory.
- Data sources: chat history only, or also documents and business data.
- Hosting: managed API or self-hosted open source.
- Integration: SDKs and framework plugins for the stack you already run.
This checklist is general advice. Check each vendor's docs and pricing page for current details.
The tools
Each option in one paragraph
Cognee
cognee.aiOpen-source agent memory platform built on graph and vector stores.
In their words: “Cognee - Open-Source Agent Memory Platform”
Letta
letta.comPlatform for stateful agents that keep long-term memory.
In their words: “Letta | Machines that learn”
Mem0
mem0.aiMemory layer that lets agents learn from past interactions.
In their words: “Mem0 - AI Memory Layer for your Agents & Apps | Persistent Context”
Supermemory
supermemory.aiMemory and continual learning engine for agents.
In their words: “supermemory, Memory and continual learning for agents”
Zep
getzep.comContext layer that unifies business data, documents, and chats for agents.
In their words: “Zep | The unified context layer for enterprise data”
Head to head
Compare them side by side
FAQ
Questions
Which memory and context layers does Agent Stack Directory list?
5: Cognee, Letta, Mem0, Supermemory, Zep.
Which of them are open source?
Cognee, Letta, Mem0 are marked open source in our data.
How is this list ordered?
Alphabetically. No placement in this guide is paid. Sponsored and featured tools are labeled elsewhere on the site and never reordered here.
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