Abstract
Service-Oriented Architectures (SOAs) are increasingly deployed to achieve distributed systems that are modular, flexible and extensible. However, designing for SOA can be challenging; there are issues involving the granularity of the cooperating services, problems with proprietary data models being exchanged, and there are no currently accepted conventions for describing a service or its interactions at an abstract level. This paper gives an overview of the Service Responsibility and Interaction Design Method (SRI-DM), an agile approach for engineering a Web Service design based on capturing a scenario as a use-case, factoring this into a set of Service Responsibility and Collaboration Cards, and constructing a Sequence diagram illustrating their interactions in fulfilling the scenario. Through two case studies the paper shows how using SRIDM can expose many of the problems of over-engineering SOA and help to create simpler, more pragmatic web service designs.