Every memory tool stores and retrieves. We store, verify, and prove.
| Capability | VerifiedState | Mem0 | Zep | Letta | Hindsight | server-memory |
|---|---|---|---|---|---|---|
| Persistent memory | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Semantic search | ✓ 768-dim | ✓ | ✓ | ✓ | ✓ | ✓ |
| Graph retrieval | ✓ | — | ✓ Graphiti | — | — | — |
| Verification receipts | ✓ Ed25519 | — | — | — | — | — |
| Conflict detection | ✓ Automatic | — | — | — | — | — |
| Temporal validity | ✓ Bitemporal | — | — | — | Partial | — |
| Governance policies | ✓ JSON engine | — | — | — | — | — |
| Zero-hop filter | ✓ 0.01ms | — | — | — | — | — |
| Real-time delta push | ✓ | — | — | — | — | — |
| Seven-channel retrieval | ✓ | — | — | — | — | — |
| Append-only / immutable | ✓ | — | — | — | — | — |
| MCP server | 16 tools | ✓ | — | ✓ | ✓ | ✓ |
| Framework integrations | 20+ | 21+ | 5+ | 3+ | 3+ | 1 |
| Free tier | 50k assertions | 1k memories | Self-host | Self-host | Self-host | Free (OSS) |
| GitHub stars | New | ~48k | ~3k | ~13k | ~2k | ~1k |
Market leader. 48k stars, $24M raised. Great memory layer for simple personalization. Gap: no receipts, no conflict detection, no governance. When two memories contradict, the newer one wins silently. Use Mem0 for simple personalization. Use VerifiedState when memory needs to be provable.
Graphiti engine is strong for temporal knowledge graphs. Scores well on LongMemEval. But no signed receipts, no policy engine. Use Zep for conversational AI with strong graph queries. Use VerifiedState when results need to be independently verifiable.
MemGPT paper, UC Berkeley. Most interesting architecture — agents manage their own memory. But it's a full agent platform, not a memory layer. Tightly coupled. Use Letta if you want agents managing their own memory. Use VerifiedState for framework-agnostic verified memory.
Clean five-tool MCP interface. Lightweight. Partial temporal support. No receipts, no conflict detection, no governance. Use Hindsight for simple MCP memory. Use VerifiedState when memory needs verification.
Simple key-value MCP server. Persists facts. That's it. Fine for prototyping. Not infrastructure.
Mem0 overwrites. VerifiedState preserves, flags, and proves.
The question isn't "which memory tool."
The question is "can you prove what your agent knew."
If the answer matters, you need receipts.
Free: 50,000 assertions/month. No credit card. No trial expiration.