The increasing importance of web-based applications and the use of new internet protocols for building service oriented applications point to new directions in the construction of this kind of systems. New challenges and problems arise when moving to a service oriented approach. Many times, the implementation of real scenarios using web services involves the use of context information according to the user needs. In this paper we provide a scalable software architecture that can be used for different types of context-aware systems and in particular in service-oriented applications.