This book constitutes the refereed thoroughly refereed post-workshop proceedings of the 17th International Conference on Web Engineering, ICWE 2017, held in Rome, Italy, in June 2017. The 24 revised full papers were selected from 34 submissions. The workshops complement the main conference, and explore new trends on core topics of Web engineering. The workshop committee accepted five workshops of which the following four contributed papers to this volume: - 2nd International Workshop on Liquid Multi-Device Software and 1st International Workshop on Engineering the Web of Things - International Workshop on The Practice Of The Open Web (practi-O-web 2017) - 3rd International Workshop on Natural Language Processing for Informal Text (NLPIT 2017) - 3rd International Workshop on Mining the Social Web (SoWeMine 2017).