Semantically enriched open API service descriptions in the cloudSemantically enriched open API service descriptions in the cloud Πλήρης Δημοσίευση σε Συνέδριο Conference Full Paper 2019-09-172018enWe propose an extension of the Open API specification (OAS) for the semantic description of RESTful services. We suggest that API descriptions (eg. on Clouds) be semantically annotated by associating OAS entities to entities in an ontology. The new approach, referred to Semantic OAS (SOAS) eliminates ambiguities and produces descriptions of RESTful services that are understandable by both, humans and machines. Moreover, SOAS descriptions are equivalent (i.e. can be translated) to an ontology. Therefore, SOAS services can be easily discovered (i.e. by other services), queried by Semantic Web query languages (e.g. SPARQL), checked by reasoners (e.g. Pellet) for consistency or inferring new (hidden) relationships and, finally, be used by service orchestration mechanisms.http://creativecommons.org/licenses/by/4.0/66-698th IEEE International Conference on Software Engineering and Service Science Mainas Nikolaos Μαϊνας Νικολαος Petrakis Evripidis Πετρακης Ευριπιδης Sotiriadis Stelios Σωτηριαδης Στελιος Institute of Electrical and Electronics Engineers Cloud computing Ontology Open API REST Web services