The 18 full research papers and 17 short papers presented together with 2 practice papers, 6 demonstration papers, and 5 tutorials were carefully reviewed and selected from 103 submissions. The papers cover research areas such as Web application modeling and engineering; Web infrastructures and architectures; execution models; human computation and crowdsourcing applications; Web application composition and mashups; Social Web applications; Semantic Web applications; Web of Things applications; big data and data analytics; and security, privacy, and identity.