Comparison
Five open frameworks, compared honestly — including what others do better. No inflated benchmark numbers, every claim verifiable.
Last updated: 19 July 2026
Most "best agent memory" lists rank by a single percentage — each on its own, often undisclosed methodology. We take a different route: five open frameworks compared soberly on verifiable properties, honest even where others are ahead of us.
The defensible head-to-head
At the same token budget, judged by three independent LLM judges, ZenBrain won all twelve of twelve pairwise comparisons on answer quality against Letta, Mem0 and A-Mem. Not our assessment — three independent judges.
| Framework | License | Self-hosting | Focus / architecture | Temporal reasoning | Benchmark evidence |
|---|---|---|---|---|---|
| ZenBrain | Apache 2.0 | Yes — complete, zero-dependency | Neuroscience-grounded 7-layer architecture: encode, consolidate, forget; sleep consolidation, spaced repetition (FSRS) | Timestamps + episodic memory | arXiv preprint + Zenodo DOI + repro script |
| Mem0 | Apache 2.0 (+ managed cloud) | Yes (open-source core) | Fact-extraction memory store with CRUD operations | Yes | Own benchmark suite |
| Zep | Graphiti Apache 2.0; Community Edition discontinued; cloud proprietary | Partial — the Graphiti engine only, not a complete system | Temporal knowledge graph (Graphiti), facts + session summaries | Strong — core focus | Own benchmarks |
| Letta | Apache 2.0 | Yes | Stateful agent runtime with self-editing memory (MemGPT lineage) | Partial | MemGPT paper (arXiv) |
| Cognee | Apache 2.0 | Yes | Graph-vector memory pipeline / knowledge graph | Yes | Own benchmarks |
Different vendors report benchmark figures on different, sometimes undisclosed methodologies (up to 95%+) — these simply are not comparable across projects. That is why there is no percentage ranking here. ZenBrain’s results instead come with method, source and a repro link on the benchmark page — verifiable, not asserted.
Bottom line
For a single building block or a managed cloud, the specialists above are strong. For a complete, self-hostable memory architecture with independently verified evidence and no cloud lock-in, there is little way around ZenBrain.