Open Source KOS software coli-conc Technical Report 2

Jakob Voß <>
Verbundzentrale des GBV (VZG)

DOI: 10.5281/zenodo.48227 (PDF)

This report gives an overview about Open Source software for Knowledge Organization Systems (KOS).


Project coli-conc aims at concordances between Knowledge Organization Systems (KOS). To manage such concordances it first requires access to KOS and its concepts. The lack of a satisfying general data format and method of access to KOS, apart from SKOS and SPARQL, resulted in the (ongoing) specification of JSKOS data format and JSKOS-API. To integrate existing KOS via these standards, there are three options:

  1. Conversion of KOS to JSKOS import into a database with support of JSKOS-API
  2. Creation of JSKOS-API wrappers to existing terminology services
  3. Add support of JSKOS-API to existing KOS software

The first option is executed at VZG for the most needed systems such as Dewey Decimal Classification (DDC) and Regensburger Verbundklassifikation (RVK). First examples of the second option are given at But only the third option will scale to larger number of KOS. Open source luckily allows to extend existing software. For this reason an overview of Open Source software for Knowledge Organization Systems (KOS) is needed.

Existing lists of KOS software (a metabibliography)

Project coli-conc does not include creation of software to manage KOS because such software already exists in form of thesaurus editors, vocabulary management systems and similar tools. The following lists of KOS software were used to find open source software (including commercial products with an open source version):

Several more lists of taxonomy tools, ontology editors etc. exists so some tools may have been missed. Feedback is welcome!

Open Source KOS software

Name and Link Language License
Apelon Distributed Terminology System (DTS) Java Apache
Django Controlled Vocabularies Python BSD
FreeMind Java Apache
iQvoc Ruby Apache
Protégé Java BSD
Semantic MediaWiki PHP GPL
SISSVoc Java & XSLT Apache
Skosify Python MIT
SKOSjs JavaScript Apache
Skosmos PHP MIT
skosprovider Python MIT
TemaTres PHP GPL
VocBench Java ?
Web Protégé Java BSD
XMind Java LGPL & EPL
VoCol Java & JavaScript MIT
Wandora Java GPL
Wikibase PHP GPL


The resulting list of software contains small and large projects, web applications and desktop applications, popular and less used software. Additional evaluation is needed to decide which products to focus on. Nevertheless the list shows that Java and PHP are the most used programming languages, so programming libraries for JSKOS(-API) should first be implemented in these languages (in addition to JavaScript which is needed for web clients). A first start has been made with a JSKOS programming library in PHP.