This volume constitutes the proceedings of the 26th International Conference on Web Services, ICWS 2019, held as part of SCF 2019 in San Diego, CA, USA in June 2019.The 11 full papers together with 1 short paper published in this volume were carefully reviewed and selected from 31 submissions.

Modeling Social Influence in Mobile Messaging Apps.- Pricing a digital services marketplace under asymmetric information.- Profit Maximization and Time Minimization Admission Control and Resource Scheduling for Cloud Based Big Data Analytics-as-a-Service Platforms.- A User Constraint Awareness Approach for QoS-based Service Composition.- AnomalyDetect: An Online Distance-Based Anomaly Detection Algorithm.- Transitive Pseudonyms Mediated Electronic Health Records Sharing for Very Important Patients.- A Novel Coalitional Game-theoretic Approach for Energy-Aware Dynamic VM Consolidation in Heterogeneous Cloud Datacenter.- An Efficient Traceable and Anonymous Authentication Scheme for Permissioned Blockchain.- A Web-Service to Monitor a Wireless Sensor Network.- Automated Hot Text and Huge Pages: An Easy-to-adopt Solution Towards High Performing Services.- ThunderML: A Toolkit for Enabling AI/ML Models on Cloud for Industry 4.0.- Study of Twitter communications on cardiovascular diseaseby state health departments.