RDF / Triple Store databases

Hybrid SQL/RDF engine that runs many of the largest public SPARQL endpoints.

Apache Jena's native RDF store, embeddable in Java or served over SPARQL with Fuseki.

Fast open-source SPARQL engine that serves all of Wikidata or OpenStreetMap from one machine.

Lisp-built RDF and document knowledge graph with vector store, reasoning and LLM agents.

Standards-compliant RDF triplestore with reasoning, connectors and MCP support for GraphRAG.

Small, fast SPARQL database in Rust that embeds in Rust, Python and JavaScript or runs as a server.

Enterprise knowledge-graph platform: RDF store, reasoning and virtual graphs over your sources.

Eclipse Foundation's Java RDF framework with native, LMDB and in-memory SPARQL stores.

Immutable RDF graph database with time travel, git-style branching, SPARQL, JSON-LD and Cypher.

In-memory RDF store with incremental Datalog reasoning, now owned by Samsung.

MIT-licensed RDF triple store for .NET with SPARQL and a LINQ-based entity framework; dormant since 2020.

MPP in-memory RDF graph database for OLAP-style SPARQL analytics, now Altair Graph Lakehouse under Siemens.

Clustered RDF quad store in C, built at Garlik for billions of triples; now receives only rare fixes.

Hosted RDF triple store with SPARQL 1.1, valid-time indexing and an MCP endpoint on every repository.

Small Windows RDF store with SPARQL, SPARQL/Update and Datalog rule inference, embeddable via Lua or DLL.

Enterprise multi-model database for XML, JSON and RDF with built-in search and semantic RAG.

Git-for-data document and knowledge-graph database with branches, diffs and time travel.

AWS's managed graph database speaking Gremlin, openCypher and SPARQL on shared storage.

Go graph database inspired by Google's Knowledge Graph, dormant since its 2019 release.

FactNexus's commercial graph DBMS that treats whole graphs as transactional units for knowledge graphs.