OWLS-SLR (SLR stands for Structural and Logic-based Reasoning) is a semantic Web service matchmaker written in Java that makes use of OWL-S Profiles. It follows the abstract Web service discovery approach, performing matchmaking based on inputs, outputs and non-functional properties. The matchmaking algorithm exploits not only the ontology subsumption hierarchy, but also the structural knowledge of the domain ontologies, such as sibling relationships among concepts.

The system was developed by Georgios Meditskos, PhD student in department of Informatics in Aristotle University of Thessaloniki, Greece, under the supervision of the assistant professor Nick Bassiliades.