Comparison · figures as of 5 September 2026
knowmind vs. Letta
Letta comes from agent research: it builds stateful agents whose memory is part of the agent itself. knowmind approaches the same need from the other side — a memory service that many agents and tools share.
What Letta offers
Letta's free tier costs $0 with a limited number of agents and your own model keys; Pro is $20 per month, and API usage is billed at $20 plus consumption. The vendor lists self-hosting as an option. If you build agents whose personality and state should live inside the agent framework, Letta is designed exactly for that.
What knowmind offers
knowmind keeps the memory outside any single agent. Whatever one tool stores is available to Claude Code, Cursor, and any other MCP client that runs a local (stdio) server — the memory survives a change of model, framework, or vendor. Every fact carries provenance, a required confidence level, and a bitemporal history; access logs are hash-chained and externally timestamped (RFC 3161). The service is operated in Germany on Hetzner (Nuremberg) with a public GDPR data processing agreement and tenant isolation. Pro is €15 per month or €150 per year; the free tier includes 2,500 memories. There is no self-hosted edition below the Enterprise on-premise option (from €1,000 per month).
How to choose
Pick Letta if the agent is the product and its memory should live inside the framework you develop in. Pick knowmind if several tools and agents need one shared memory that outlives each of them, and if you have to show later where a fact came from and what the system knew at a given date. At $20 against €15 the prices are close, so the decision is about where the memory should live.
| Free tier | First paid tier | Self-hosting | |
|---|---|---|---|
| Letta | limited agents, own keys | $20/month | yes (per vendor) |
| knowmind | 2,500 memories | €15/month | no (Enterprise on-premise option) |
Lettaprices and tiers were taken from the vendor's public pricing page on 5 September 2026; knowmind's own figures come from knowmind.de/pricing and our product documentation. If you find something outdated, tell us and we will correct it.
Other comparisons
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