Today there is a countless number of applications developed for the World Wide Web. These applications have user interfaces that should be able to adapt to several usage scenarios, content and context changes and also to be compatible with multiple browsers and devices. Furthermore, the design and maintenance of interfaces that need adjustments depending on the business rules of the application require much effort during the development life cycle of an application. In order to assist in the design of these interfaces, some UIDL s (User Interface Description Languages) have been proposed aiming at providing a level of abstraction so that the designer does not need to immediately focus attention on concrete aspects during the development of an interface. This work presents a proposal for modeling and generating interfaces of web applications based on production rules. These rules define criteria for situations determining the activation of an interface; for the selection the elements that participate in the abstract composition and also for the mapping of specific widgets that will be used in the rendering stage. The proposal contemplates a method for modeling interfaces, an implementation architecture and a framework for authoring and execution of the proposed interface models. An architecture is also presented for building widgets as well as a concrete interface interpretation and rendering machine from a hierarchy specification. The overall goal of the proposal is to design interfaces more responsive to data and contexts of use, including situations of adaptation, generating more flexible and reusable interfaces.