Graphiti
OSS temporal knowledge graph engine purpose-built for AI agents. The engine underneath Zep, also usable standalone. Tracks facts and their validity over time so agents can reason about state changes, not just current truth.
Mem0
Open-source persistent memory layer that gives AI agents the ability to remember users, preferences, and context across sessions. Supports vector, graph, and key-value storage backends. AWS partner for Strands Agents. YC W23, $24M raised, 30K+ GitHub stars.