A method and system for dynamically generating web based user interfaces. In one embodiment, a method is disclosed for displaying a user interface over a network to a user. The method begins by reading an HTTP request for authentication from a browser associated with the user. The HTTP request comprises credential information associated with the user. Based on the credential information, a first plug-in module from a plurality of plug-in modules is invoked to authenticate the user. Also, each of the plurality of plug-in modules provide similar authentication services. An authentication user interface is dynamically generated based on the HTTP request and configuration properties that are defined by the first plug-in module.