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Head-to-head · Knowledge Graph Software

Protégé vs Stardog

  • Updated Oct 2026
  • Both researched from official sources
  • 5 checks side by side
Higher score Protégé #2 in Knowledge Graph Software 9.1/10 Free plan Free plan✓ 4 of 4 features Visit Protégé
Stardog #5 in Knowledge Graph Software 8.8/10 Free plan Free plan✓ 0 of 4 features Visit Stardog

Protégé leads on 0 checks, Stardog on 0, and 5 are even. Who comes out ahead on the 5 yes/no, price and count checks where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scoreProtégé · 9.1/10
  • Free planboth
  • Most featuresProtégé · 4 of 4

Protégé scores higher on our rubric for knowledge graph software: 9.1 against 8.8 out of 10; our editors rank them #2 and #5.

Protégé is the better fit for ontology engineers and collaborative OWL modeling. Stardog is the better fit for federated knowledge graphs across enterprise data.

  • Protégé fits best

    Ontology engineers and collaborative OWL modeling

  • Stardog fits best

    Federated knowledge graphs across enterprise data

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Side by side

Feature Protégé 9.1/10 Visit ↗ Stardog 8.8/10 Visit ↗
At a glance
Editor score 9.1 8.8
Ranking #2 in Knowledge Graph Software #5 in Knowledge Graph Software
Best for Ontology engineers and collaborative OWL modeling Federated knowledge graphs across enterprise data
Pricing model Free Free plan + paid
Starting price Free plan —
Free plan ✓ ✓
Free trial — —
Deployment Cloud, Desktop Cloud, Self-hosted
Platforms Web, Windows, macOS, Linux Web
Support Community, Docs Community, Docs · 24/7
Built for Solo, Small business, Mid-market, Enterprise Mid-market, Enterprise
Features Protégé 4/4 · Stardog 0/4
Ontology modeling ✓ (best) Not checked yet
Semantic reasoning ✓ (best) Not checked yet
RDF/SPARQL support ✓ (best) Not checked yet
Graph visualization ✓ (best) Not checked yet
Specs
Import formats RDF/XML, Turtle, OWL/XML, OBO Not checked yet
Deployment Both Not checked yet
Query languages SPARQL Not checked yet
Our review
Pros
  • Free and open source across desktop and browser-based workflows
  • Supports OWL 2, RDF, reasoning, visualization, querying, and refactoring
  • Adds collaboration, permissions, revision history, and plug-in extensibility
  • Queries remote data through virtual graphs without necessarily moving it
  • Supports SPARQL, SQL, GraphQL, REST, inference, and ontology management
  • Offers both managed cloud and self-managed enterprise deployment
Cons
  • Primarily focused on ontology development rather than operational graph management
  • SPARQL is documented as a plugin for Protégé-OWL 4.2
  • Collaborative WebProtégé workflows differ from local desktop editing
  • The Free plan is limited to 1 million stored edges
  • Enterprise pricing requires contacting sales
  • It is proprietary rather than open source
Our verdict

Protégé is a free, open-source ontology development environment for researchers, organizations, and governments. It combines Protégé Desktop, which runs locally, with WebProtégé, a browser-based editor for collaborative work without…

Read the review →

Stardog is a knowledge-graph and semantic AI platform for enterprises that need to connect and query distributed data. Its virtual graphs and connectors work with relational, NoSQL, file, cloud, and SPARQL sources, while SPARQL, SQL-based…

Read the review →
  1. ProtégéKnowledge Graph Software 9.1Free plan
  2. StardogKnowledge Graph Software 8.8Free plan

Strengths and trade-offs

  • Protégé — where it wins

    • Free and open source across desktop and browser-based workflows
    • Supports OWL 2, RDF, reasoning, visualization, querying, and refactoring
    • Adds collaboration, permissions, revision history, and plug-in extensibility

    Where it doesn't

    • Primarily focused on ontology development rather than operational graph management
    • SPARQL is documented as a plugin for Protégé-OWL 4.2
    • Collaborative WebProtégé workflows differ from local desktop editing

  • Stardog — where it wins

    • Queries remote data through virtual graphs without necessarily moving it
    • Supports SPARQL, SQL, GraphQL, REST, inference, and ontology management
    • Offers both managed cloud and self-managed enterprise deployment

    Where it doesn't

    • The Free plan is limited to 1 million stored edges
    • Enterprise pricing requires contacting sales
    • It is proprietary rather than open source

More comparisons

All knowledge graph software comparisons → · Full ranking →

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update