Concept and vocabulary services have been migrated to Skosmos

As of February 2024, the CLARIN Concept Registry (CCR) and the CLARIN Vocabulary Service (CLAVAS) have been migrated to a new system based on Skosmos.

Skosmos is a an open source web-based SKOS browser and publishing tool that has gained a lot of traction over the last coupe of years. It has a well defined and functionally rich REST API that provides a solid basis for wide interoperability.

The CCR functions as a central hub within the CLARIN infrastructure for concepts, which are used in CMDI among other places to achieve semantic alignment, enabling, for instance, faceted search in the VLO.

CLAVAS is CLARIN’s central provider for controlled vocabularies. Like the CCR, it is based on concepts and schemes defined using SKOS.

In brief, the changes that are most visible and may be relevant to end users of CLARIN’s metadata infrastructure are:

  • User interface changes: Skosmos has its own modern and easy to use web front end.
  • API changes: both the locations (paths) and the content and format of responses have changed. The root of the service that includes all vocabularies including the CCR vocabulary (in Skosmos terms) is As an example call, the list of vocabularies may be retrieved at […]/rest/v1/vocabularies?lang=en. We refer to the Skosmos REST API documentation for details.
  • The Component Registry has been adapted to use the renewed services. Searching for concepts or vocabularies in the Component Editor has not changed functionally but is now backed by the new Skosmos based service instances.

It’s important to note that the concept identifiers, which take the shape of handles (for example: “annotation format” – have not changed and have been updated to resolve to the concept page in the Skosmos front end.

We hope to use the Skosmos platform as a base for expanding the central offer of vocabularies and concepts on the one hand, and implementing widened interoperability on the other hand – this switch constitutes an important step towards integration of other Skosmos based or compliant services into CLARIN’s metadata infrastructure.

Feel free use the comments feature below this forum post for questions, feedback or discussion about the migration to Skosmos!