HydraDB

HydraDB is building the graph-native context and memory infrastructure for AI. AI is stateless — HydraDB fixes that with graphs: instead of similarity search over a vector store, it builds structured context graphs of entities, relationships, temporal states, and causal chains, returning relevance instead of similarity. The product is a GraphDB built on object storage with a tiered architecture (in-memory cache → NVMe → object storage), git-style temporal versioning, and entity resolution — roughly 10x cheaper and purpose-built for modern AI workloads. Born out of research at Stanford, HydraDB has raised $6.5M from investors including Jeff Dean, Sky9 Capital, and researchers from OpenAI and DeepMind. Over 2,000 developers build on it today, with 1B+ documents ingested.