1. A financial transaction system for supporting communication between a plurality of financial institution customers and at least one financial institution back end processing system comprising: an application service program for processing client requests from a client program executing on a computer associated with at least one of the customers; a client interface for communicating messages between said client program and said application service program; a host interface for coupling said application service program to a back end processing system for a financial institution; and a local data memory coupled to said application service program, said local data memory for storing customer data refreshed with data received through said host interface, said application service program processes said client messages received through said client interface with said customer data stored in said local data memory.