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Tool Overview


Protégé is a free, open source ontology editor and knowledge-base framework. The Protégé platform supports two main ways of modeling ontologies via the Protégé-Frames and Protégé-OWL editors. Protégé ontologies can be exported into a variety of formats including RDF(S), OWL, and XML Schema. Protégé is based on Java, is extensible, and provides a plug-and-play environment that makes it a flexible base for rapid prototyping and application development.

Protégé software is currently transitioning from the current version (Protégé 3.X) to an entirely new release (Protégé 4.x). Protégé 3.X is widely used and the adoption of Protégé 4 is slowing happening. Because of this, you will find resources for both versions.

If you are interested in the current difference between the two, please read the comparison on the Stanford website Exit Disclaimer logo .

Installation and Downloads

As Protégé is an open source product, downloads are available through the Stanford Protégé site:
Downloads for Protégé 3 and Protégé 4 Exit Disclaimer logo

The Code Repository can be found at these Stanford sites:

Forum and Support

The Protégé Bug Tracker can be found on a Stanford service: Protégé Bugzilla Exit Disclaimer logo

What's New

Protégé 4.1 Release

July 26, 2011

The highlights of this release are:

  • Full conformance with the OWL 2.0 language specification
  • Automatic update mechanism for distributing new features and bug fixes
  • New application bundle format distribution for the OS X community
  • Direct, in-memory connection to the HermiT and FaCT++ reasoners

For further information, please visit:

Protégé 3.4.8 Release

January 12, 2012

The highlights of this release are:

For further information, visit:

For information about previous versions of Protégé, please visit Protégé Past Versions.

Documentation and Training

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