: This article presents a mediation framework supporting the integration of web services in orchestrated and choreographed services and the conciliation of interaction protocol mismatches. Our framework supports a loosely-coupled interaction among web services, based on the publish and subscribe pattern. Moreover, it manages web services as event-driven systems, in order to enable them to perform their operations in context-dependent way. By decoupling the web service interaction, our framework addresses several interaction protocol mismatches, ranging from differences in the signatures of the messages, to the order and number of the messages to be exchanged, including cross-protocol mismatches involving more than two peers.