Web Service Interaction Ontology (WSIO) enables automated interaction with more complex Web services that are typical for example within life sciences. WSIO is however independent of the application domain and relevant for both SOAP and REST Web services, and for batch execution engines in general. If the interaction scenario with a Web service is nontrivial (and incorporates session handling), annotation with WSIO concepts will enable automatic generation of client programs, scripts, or interactive applications with a graphical user interface. WSIO also enables automation of different ways of data transfer and data un-/compression or en-/decoding. We strongly discourage providers from developing complex interaction and data-transfer/compression scenarios, however when needed, WSIO may enable smooth automated interaction with them. Future versions will support more interaction scenarios. WSIO aims to serve also as a means to standardise the complex interaction scenarios primarily within both SOAP and REST Web services, and secondarily to apply also to batch execution infrastructure in general.