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Protégé

Free#2 of 33 in Knowledge Graph Software

Protégé: A strong free choice for OWL ontology work, with collaboration and reasoning options. Ranked #2 of 33 in Knowledge Graph Software by our editors (9.1/10); pricing: Free plan; best for ontology engineers and collaborative OWL modeling.

9.1/10Editor score

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Protégé9.1 Visit Protégé

At a glance

Editor score
9.1 / 10
Pricing
Free plan
Best for
Ontology engineers and collaborative OWL modeling
Free plan
Yes
Paid from
Free
Semantic reasoning
Yes
Facts checked
21 Sep 2026

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

Our verdict on Protégé

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 installation. Its core audience is ontology engineers and teams creating, reviewing, and maintaining OWL 2 and RDF models. The feature set covers ontology modeling and refactoring, description-logic reasoning with HermiT and Pellet, structure visualization, querying, and multiple import and export formats.

The product’s cost structure is straightforward: both Desktop and WebProtégé are described as free and open source. That makes it suitable for teams that need formal ontology tooling without a paid plan structure. WebProtégé adds collaborative editing with permissions, threaded discussions, notifications, revision history, and change tracking. Desktop provides a local editing environment, while the web option supports shared browser-based workflows. Together, these modes address individual ontology development and team review without requiring every contributor to work in the same environment.

Protégé fits organizations that need focused OWL development, semantic reasoning, RDF support, and visualization across Windows, macOS, Linux, and the web. Plug-in extensibility broadens the environment, and SPARQL support is documented through a plugin compatible with Protégé-OWL 4.2, so teams should validate that integration against their deployment. Protégé is a strong pick for ontology design and collaborative knowledge-model maintenance. Teams seeking a broader operational graph platform should consider whether its ontology-centered focus matches their architecture and workflow.

Your product? Our editors can test Protégé in depth and publish a review, labelled as paid · from $149/mo →

Protégé pricing

Plans Free planFree Free to use — no paid tier required for the core job.

See plans on protege.stanford.edu

Protégé fact sheet

Free plan	Yes
Paid from	Free
Ontology modeling	Yes
Semantic reasoning	Yes
RDF/SPARQL support	Yes
Graph visualization	Yes
Import formats	RDF/XML, Turtle, OWL/XML, OBO
Deployment	Both
Query languages	SPARQL
Deployment	Cloud, Desktop
Platforms	Web, Windows, macOS, Linux
Support	Community, Docs
Built for	Solo, Small business, Mid-market, Enterprise (editorial estimate)
Pricing	Free plan
Website	protege.stanford.edu
Facts checked	21 Sep 2026

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Featured on iTechGuides

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update