AI agent memory tools
An agent without memory starts every session from zero. These tools fix that in three places. Mem0, Zep, Supermemory and Maximem Synap are memory layers you build into your own agent: they pull facts out of conversations and hand back the right ones before the model replies. Letta puts the memory inside the agent itself. DocuMemory and Skillsync are for you: they keep what you worked out with Claude Code, Cursor or ChatGPT where your next session can find it. 7 tools, in the order they appear in the directory. This is not a ranking.
Grouped by job: Claude Code Tools · AI Agent Infrastructure
DocuMemory
Memory engine for AI-first engineers: distils Claude Code, ChatGPT and Cursor sessions into architecture decisions and prompt-injectable context blocks, recalled over MCP or a REST API; 15 free distillations, then from $10/month.
Maximem Synap
Memory and context layer for AI agents with entity resolution, temporal reasoning and scoping built in, sub-15ms recall, a hosted MCP endpoint and native adapters for 23 agent frameworks including LangChain and the Claude Agent SDK; free tier, paid from $19/month.
Skillsync
Mac app and CLI that searches all your past coding-agent sessions before each prompt and hands your agent a short recollection with sources; works with Claude Code, Codex, Cursor, OpenCode, Amp and more, indexes locally, with shared team workspaces.
Mem0
Memory layer for AI agents and apps: send it conversations and it extracts, updates and retrieves the memories that matter for each user, through Python and Node SDKs, an API, MCP and a CLI. Open source (Apache-2.0) as a library or self-hosted server, or the hosted platform with a free plan.
Zep
Context and memory layer for AI agents: turns conversations, documents and business data into a temporal Context Graph per user, account or domain, with dated facts traced to their source and retrieval under 200 ms. Zep Cloud, your own encryption keys or your VPC; its graph engine Graphiti is open source (Apache-2.0). Free 10,000 credits a month.
Letta
Stateful agents with memory that persists and improves with experience, from the makers of MemGPT: Letta Code ships a terminal UI, an app server for self-hosted agents and an Agent SDK, with Letta Cloud to carry memory across machines. Open source (Apache-2.0); free with your own API keys, Pro $20/month.
Supermemory
Memory and context engine for AI agents: learns from each user's chats, files and URLs, stores it in a vector-graph database and injects what matters into your agent's context, through an API, MCP and plugins for Claude Code, Cursor and more. Open source (MIT); hosted free plan with $5 of credits a month, Pro $19/month.
What it remembers, where it runs, what it costs.
Straight from each vendor's own pages. Plans move often, so the check date is below.
| Tool | Remembers | Runs on | Open source | Price |
|---|---|---|---|---|
| DocuMemory | What you worked out with AI: chats saved as decision docs and short memories any connected tool can search. | Hosted. MCP over Streamable HTTP, Claude and ChatGPT connectors, and a REST API. | No. Hosted service, source not public. | 15 free distillations, no card. Personal $10/mo, or $8/mo billed yearly. Team $15/seat/mo, 2-seat minimum. |
| Maximem Synap | Your agent's users and organisation: facts with entity resolution, scoped per user, customer and tenant. | Hosted API, Python and TypeScript SDKs, an MCP endpoint and adapters for 23 agent frameworks. On-prem on Enterprise. | SDK and eval harness are Apache-2.0. The engine is hosted. | Trial free: 12,500 credits a month. Starter $19/mo at launch price. Pro $249/mo. Scale $999/mo. |
| Skillsync | Your own coding-agent sessions, searched before every prompt and handed back as a short recollection with sources. | Mac app, indexing on your Mac. skl CLI for Linux, Windows and remote servers. | txcript, its tool for moving sessions between agents, is Apache-2.0. | Open source free. Pro $20/seat/mo with a 5-day trial, no card. Team custom. |
| Mem0 | Your app's end users: memories extracted from conversations, updated as things change, retrieved on each turn. | Hosted platform, or the library and a self-hosted server via Docker. On-prem on Custom plans. | Yes, Apache-2.0. | Free: 50,000 adds and 10,000 retrievals a month with your own LLM key. Custom plans add graph memory, SSO and on-prem. |
| Zep | Users, customers, accounts or domains: a temporal Context Graph built from conversations, documents and business data. | Zep Cloud, Zep Cloud with your own encryption keys, or your VPC on Enterprise. | Graphiti, its graph engine, is Apache-2.0. Zep itself is hosted. | Free: 10,000 credits a month. Flex $125/mo. Flex Plus $375/mo. Enterprise custom. |
| Letta | The agent itself: memory, identity and skills that persist and improve with experience. | Letta Code in the terminal, desktop and web apps, a self-hosted app server, or Letta Cloud. | Yes, Apache-2.0. | Free with your own API keys, limited agents. Pro $20/mo, up to 20 stateful agents. API plans are usage-based. |
| Supermemory | Users, tasks and tenants: learns from chats, files and URLs and injects what matters into context. | Hosted API, MCP and plugins for Claude Code, Cursor and more. Self-hosted on Scale and Enterprise. | Yes, MIT on GitHub. | Free with $5 of credits a month. Pro $19/mo. Max $100/mo. Scale $399/mo. |
Checked 2026-10-31. Sources: Mem0 pricing, Mem0 on GitHub, Zep pricing, Graphiti on GitHub, Letta pricing, Letta Code on GitHub, Supermemory pricing, Supermemory on GitHub, Maximem Synap pricing, Synap SDK on GitHub, DocuMemory, Skillsync pricing, txcript on GitHub.
Pick it if.
- Mem0You want an open-source memory layer you can self-host, or start free on the hosted plan with your own LLM key.
- ZepYour agents need facts from business data and documents, not just chat, with dates, sources and access policies.
- SupermemoryYou want memory and document retrieval behind one API, plus plugins for the coding agents you already use.
- Maximem SynapYou're building a support or voice agent and need per-user and per-tenant memory that comes back fast.
- LettaYou want an agent that keeps its own memory and gets better over time, not a memory API to wire in.
- DocuMemoryYou work things out across Claude, ChatGPT and Cursor and want the decisions written up where all of them can read them.
- SkillsyncYou keep re-solving problems in Claude Code or Codex that an old session already cracked.
Each listing.
The directory page, alternatives in the same category, and a head-to-head where we have one.
- DocuMemoryAlternatives
- Maximem SynapAlternatives
- SkillsyncAlternatives
- Mem0Alternatives
- ZepAlternatives
- LettaAlternatives
- SupermemoryAlternatives
Category pages list every tool in those categories, including ones left off this page. Built one of these? Get it featured in its category.
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