International audienceService-based infrastructures are shaping tomorrow's distributed computing systems by allowing the design of loosely-coupled distributed applications based on the composition of services spread over a set of resources available on the Internet. Compared to previous approaches such as remote procedure call, distributed objects or components, this new paradigm makes feasible the loose coupling of software modules, encapsulated into services, by allowing a late binding to them at runtime. In this context, an important issue is how to express the composition of services while keeping this loosely-coupled property. Different approaches have been proposed to express services composition, mostly using specialized languages. T...