This site is here for historical reasons.

All development happens on the GitHub site.

The code can be found at this link.

Ancient releases are here.

Download the latest release or search for it on Maven Central.

The OWL API is a Java API and reference implmentation for creating, manipulating and serialising OWL Ontologies. The latest version of the API is focused towards OWL 2

For the latest updates, code and documentation, please visit the new GitHub web site.

The OWL API is open source and is available under either the LGPL or Apache Licenses

The OWL API includes the following components:

  • An API for OWL 2 and an efficient in-memory reference implementation
  • RDF/XML parser and writer
  • OWL/XML parser and writer
  • OWL Functional Syntax parser and writer
  • Turtle parser and writer
  • KRSS parser
  • OBO Flat file format parser
  • Reasoner interfaces for working with reasoners such as FaCT++, HermiT, Pellet and Racer

The original version of the API for OWL 1.0 was developed as part of the WonderWeb Project. Version 2.0.0 of the OWL API for was developed as part of the CO-ODE project and the TONES project. Version 3.0.0 is developed primarily at the University of Manchester.


The OWL API is primarily maintained at the University of Manchester, but there have been significant contributions from various groups and companies:


OWL API development is supported by various free open source licenses:

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Note that the web pages for version 2 of the OWL API may be found here. Version 3.0.0 pages are available here.

Both are here for reference; those versions of the API are not recommended for new starters.