Distributed Ontology Management Environment
- DOME is developed by the Ontology Management Working Group. The aim is to provide tooling support for editing, browsing, versioning, evolution, mapping and merging of ontologies.
- http://dome.sourceforge.net/

WebODE Performance Benchmark Suite
- Developed in order to evaluate the performance of the WebODE ontology engineering workbench.
- http://kw.dia.fi.upm.es/wpbs/

pOWL
- pOWL is web-based knowledge base edititing and management solution for the Semantic Web. It supports collaborative browsing, querying and editing of RDFS/OWL Ontologies and exposes an extensive API for PHP programmers.
- http://powl.sourceforge.net

DOE - The Differential Ontology Editor
- A simple ontology editor allowing to build ontologies according to a methodology proposed by Bruno Bachimont. Supports OWL, DAML+OIL and RDFS formats. Free download.
- http://opales.ina.fr/public/

F-OWL
- An ontology inference engine for OWL, using Flora-2, an object-oriented knowledge base language and application development platform.
- http://fowl.sourceforge.net/

The Chimaera Ontology Environment
- A merging and diagnostic ontology environment. It is distributed for external use and has been used in academics and also commercially.
- http://www.ksl.stanford.edu/software/chimaera/

RACER System
- A Semantic Web inference engine for developing ontologies and query answering over RDF, RDFS/DAML or OWL.
- http://www.sts.tu-harburg.de/~r.f.moeller/racer/

Pellet OWL Reasoner
- An on-line tool providing various reasoning services for OWL documents, such as OWL species, consistency checking, satisfiability, entailment test.
- http://www.mindswap.org/2003/pellet/demo.shtml

IBM Ontology Management System
- A framework for loading ontologies from files and via the Internet and for locally creating, modifying, querying, and storing ontologies.
- http://www.alphaworks.ibm.com/tech/snobase

WordMap Taxonomy Management Software
- Allows an organisation to ensure semantic interoperability of metadata, through consistent terminology in all of its applications, assets and activities.
- http://www.wordmap.com

EON2002 - Evaluation of Ontology-based Tools
- Program and Proceedings of OntoWeb-SIG3 Workshop at the 13th International Conference on Knowledge Engineering and Knowledge Management.
- http://km.aifb.uni-karlsruhe.de/eon2002

Dumpont
- A simple web service allowing to display class and property hierarchies from a DAML or OWL file.
- http://www.daml.org/2001/03/dumpont

OWL Ontology Validator
- An on-line tool that identifies an ontology as OWL Lite, OWL DL, or OWL Full.
- http://phoebus.cs.man.ac.uk:9999/OWL/Validator

Ontology Works, Inc.
- Makers of ontology engineering tools for enterprise information integration.
- http://www.ontologyworks.com

Open Cyc
- OpenCyc is the open source version of the Cyc technology, the world's largest and most complete general knowledge base and commonsense reasoning engine.
- http://www.opencyc.org

Ontolingua
- A distributed collaborative environment to browse, create, edit, modify, and use ontologies. Provided by the Knowledge Systems Laboratory of Stanford University.
- http://www.ksl.stanford.edu/software/ontolingua/

Apollo
- A knowledge modelling Java application developed by the Knowledge Media Institute. Internal model is build as a frame system conformant to OKBC protocol. Version 1.1 supports OWL.
- http://apollo.open.ac.uk/index.html

OilEd
- OilEd is a free ontology editor supporting DAML+OIL, developed by the University of Manchester. Download available. Latest version supports OWL.
- http://oiled.man.ac.uk/

Ontology Building: A Survey of Editing Tools
- Survey of ontology editing tools summarizes more than 50 software tools and provides a brief introduction to the topic. Includes resources.
- http://xml.coverpages.org/Denny-OntologyEditorSurveyText20021111.html

Protégé
- A free open-source Java tool providing an extensible architecture for the creation of customized knowledge-based applications. Includes documentation, events and publications.
- http://protege.stanford.edu/