Free and open first
Best Knowledge Graph Software in 2026
Knowledge graph software supports work with connected data, from modeling relationships to querying them. Compare ontology modeling, graph visualization and import formats, then consider deployment options and the listed query languages. RDF/SPARQL support and semantic reasoning can help distinguish the approaches shown. RDFox, AllegroGraph and Eclipse RDF4J are among the options to examine. Free-plan availability and paid-from pricing offer cost context. Consider the formats and modeling capabilities relevant to your data, as well as the ways you need to query or reason over its connections.
- 33 apps
- Research read 23 Sept 2026
- How the order is worked out
- 1
Apache Jena Fuseki
Free plan Open source APILinuxSelf-hosted+2Apache Jena Fuseki combines SPARQL protocols with several deployment modes and TDB storage. Check the graph-level access-control limit and default endpoint exposure when planning a deployment.
- 2
Eclipse RDF4J
Free plan Open source APILinuxMac+3RDF4J brings RDF storage, querying and reasoning tools together in a Java framework, with several storage options and a broad format list.
- 3
LinkedDataHub
Free plan Open source APILinuxMac+3Pick LinkedDataHub if you need a free, self-hosted platform for working with RDF data, SPARQL, and knowledge-graph applications.
- 4
Protégé
Free plan Open source APILinuxMac+3Protégé combines a collaborative browser editor with a desktop ontology workspace, and both support OWL 2.
- 5
Virtuoso Universal Server
Free plan Open source APILinuxMac+3Choose Virtuoso if you need a multi-model database that can present data from different sources through one view, with both open-source and commercial licensing available.
- 6
AllegroGraph
Free plan APILinuxMac+3AllegroGraph brings graph, vector, reasoning, and analytics capabilities into one platform. The free edition’s triple cap and Linux-native server deployment are important selection considerations.
- 7
eccenca Corporate Memory
Free plan APILinuxSelf-hosted+1Corporate Memory combines semantic modeling, data integration, governance, and multiple access interfaces for enterprise knowledge graph work.
- 8
GraphDB
Free plan APILinuxMac+3GraphDB combines semantic data modeling and reasoning with a range of listed AI capabilities and integrations.
- 9
HASH
Free plan APIExtensionSelf-hosted+1Choose HASH if your organization needs a connected information model for workflows, analytics, simulations, or agents, with historical states and provenance.
- 10
- 11
Oxigraph
Free plan APILinuxSelf-hosted+1Oxigraph combines RDF storage, SPARQL support, language bindings, and a command-line server in a free toolkit.
- 12
QLever
Free plan APILinuxMac+3QLever brings SPARQL, text search, query assistance, and spatial features to self-hosted RDF data.
- 13
Ontop
Free plan APILinuxMac+3Choose Ontop if you need an open source way to expose relational databases as virtual knowledge graphs and query them with SPARQL.
- 14
RDF Studio
Free plan APILinuxMac+2RDF Studio brings query, ontology, and SHACL work into a single semantic data workspace. Its preview status and stated reasoning limitation make the maker’s test-data guidance important.
- 15
Stardog
Free plan AndroidAPIiPhone+5Stardog offers data virtualization, semantic querying, and knowledge-graph tools across several deployment options.
- 16
TerminusDB
Free plan APILinuxSelf-hosted+1Choose TerminusDB if your work needs a schema-enforced document graph with Git-like version control, transactional commits, and multiple query interfaces.
- 17
TypeDB
Free plan APILinuxMac+3TypeDB is built around schema validation and relations that can represent connections among entities, attributes, and other relations.
- 18
- 19
metaphactory
Free trial APILinuxSelf-hosted+1metaphactory combines knowledge-graph modeling, governance, discovery and AI assistance for enterprise data environments.
- 20
OWLGrEd
Free plan WebWindows - 21
PoolParty Semantic Suite
Free trial APILinuxSelf-hosted+1PoolParty Semantic Suite provides tools for modeling, enriching, querying, and visualizing semantic data. Its deployment choices and broad import support serve complex enterprise knowledge projects.
- 22
Progress Semaphore
Free trial APILinuxSelf-hosted+2Semaphore brings knowledge modeling, semantic metadata, and enterprise data into generative AI workflows. Its trial provides broad access for 30 days, while pricing requires an inquiry.
- 23
Fluent Editor
Free plan WindowsPick Fluent Editor for free, self-hosted ontology work on Windows, especially when semantic reasoning, RDF/SPARQL and graph visualization are all needed.
- 24
RDFox
Free trial APILinuxMac+3RDFox combines RDF storage, SPARQL querying, reasoning and multiple deployment options.
- 25
Timbr
Free trial APILinuxSelf-hosted+1Timbr combines semantic modeling, virtualized cross-source queries, and AI development integrations. Check plan limits carefully if data virtualization or self-hosting is required.
#1Places #1, #2, #3, #4, #5 on this list can be bought by the makers of the software on it. See the price
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