Ontop4theWeb: SPARQLing the Web On-the-fly

Web data come in many different structures and formats that are not supported by Semantic Web tools. To leverage them, we propose a system, called Ontop4TheWeb, which allows for mapping Web data of various formats into virtual RDF triples and querying them on-the-fly without materializing them as RDF triples. We put our system into practice, querying with SPARQL diverse Web data sources that range from HTML tables to REST APIs, such as social media APIs. Our thorough experimental evaluation demonstrates the high efficiency of our approach, which goes beyond the current state-of-the-art in this area, in terms of both functionality and performance.