This book constitutes the refereed proceedings, presented on the 20th International Conference on Web Information Systems Engineering, WISE 2019 and on The International Workshop on Web Information Systems in the Era of AI, held in Hong Kong and Macau, China. Due to the problems in Hong Kong, WISE 2019 has been postponed until January 2020.The 7 workshop papers, 5 demo papers and 3 tutorial papers presented were carefully reviewed and selected from numerous submissions. The papers are organized in the following sections: tutorials; demos; the International Workshop on Web Information Systems in the Era of AI.