An important factor in the successful deployment of federated web-services-based business activities will be the ability to guarantee reliable distributed operation and execution. Failure management is essential for any reliable distributed operation but especially for the target areas of web-services, where the activities can be constructed out of services located at different enterprises, and are accessed over heterogeneous networks topologies. This paper describes ws-membership, a coordination service that provides a generic web-service interface for tracking registered web-services and for providing membership monitoring information. A prototype membership service based on epidemic protocol techniques has been implemented and is described in detail in this paper. The specification and implementation have been developed in the context of the Huygens project which focuses global scalable distributed systems based on web-service technologies. Categories and Subject Descriptors C.2.1 ...