1. A system for building configurable applications, the system comprising. a distributed tier including: (i) a presentation module accessible by a user, the presentation module being configured to permit configuration of an interface in a session with the user, the session generating state data including at least one indication of a modification to the interface, and, (ii) an interface module configured to process at least a portion of the state data in an extensible language format; a mainframe system including: (i) an enterprise architecture integration (EAI) framework configured for receiving the extensible language formatted state data and invoking at least one service in association with evaluating the extensible language formatted state data, and (ii) a business rules engine having at least one rule based on an extensible language format, the business rules engine being accessible by the EAI framework in association with evaluating the state data; and, the mainframe system being configured to translate the evaluated state data into a reply message based on an extensible language format.