Web-based portals are a convenient and effective mechanism for integrating information from a wide variety of sources, including Web services. However, since availability and performance of Web services cannot be guaranteed, availability of information and overall performance of a portal can vary. In this paper, we describe a framework for developing an autonomic self-healing portal system that relies on the notion of differentiated services (i.e., services that provide common behavior with variable quality of service) in order to survive unexpected traffic loads and slowdowns in underlying Web services. We also present a theoretical performance model that predicts the impact of the framework on existing systems. We demonstrate the framework with an example and provide an evaluation of the technique.