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Pellet: OWL 2 Reasoner for Java

Pellet is an OWL 2 reasoner. Pellet provides standard and cutting-edge reasoning services for OWL ontologies.

Download Pellet

Download Pellet to get started.

Pellet on Github

If you’d prefer to build from source code or contribute fixes and changes, fork Pellet on Github.


For applications that need to represent and reason about information using OWL, Pellet is the leading choice for systems where sound-and-complete OWL DL reasoning is essential. Pellet includes support for OWL 2 profiles including OWL 2 EL. It incorporates optimizations for nominals, conjunctive query answering, and incremental reasoning. There’s more detailed information about the architecture of the system and its features in Pellet Help.

An OWL DL reasoner like Pellet is a core component of ontology-based data management applications; if you need expertise in the use of Pellet for advanced integration or analysis applications, Clark & Parsia LLC can help in a variety of roles: consulting, application development, and OEM licensing.

Dual License Model

Pellet is available under dual licensing terms:

  1. For open source applications, Pellet may be used under the terms of the AGPL version 3 license.
  2. For proprietary, closed source applications, and other commercial applications, Pellet is available under alternative license terms; please direct inquires to Clark & Parsia.

For more information, see the discussion Pellet’s dual license model.

Commercial Technical Support

We provide commercial support contracts for Pellet and other components of our semantic web infrastructure. If you need commercial support, get in touch via email or visit the Pellet commercial support site.

Community Support

Community-based support is available at pellet-users mailing list