In this paper we present a tool to syntactically and semantically validate SPARQL queries. With this aim, we extract triple patterns and filter conditions from SPARQL queries and we use the OWL API and an OWL ontology reasoner in order to detect wrong expressions. Given an ontology and a query, the tool reports different kinds of programming errors: wrong use of vocabulary, wrong use of resources and literals, wrong filter conditions and wrong use of variables in triple patterns and filter conditions. When the OWL ontology reasoner is used the tool reports a diagnosis.
