The service-oriented computing offers an ideal development framework for carrying out business processes related to the dynamic management of component-based web user interfaces. This article proposes an architecture for specification, storage, management and visualization of web user interfaces built from widgets that follow the recommendation of the W3C. It describes a Widgets-as-a-Service (WaaS) approach for interface deployment and a three-level data model for the definition of components that take part in the architecture. In addition, it shows some particularities of the used technology and the implementation developed. To illustrate this proposal, an example of WaaS-based graphical interface developed for the Environmental Information Network of Andalusia (REDIAM) is shown.