1. An application gateway server for managing communication between component application executing in a runtime environment on a device and at least one backend server; the application gateway server comprising: (a) a message listener for receiving messages from the component application; (b) a connector subsystem comprising a plurality of connectors, each of the plurality of connectors for communicating with one or more associated backend servers; (c) a messaging subsystem comprising: (i) a message broker for processing the messages received from the message listener and transmitting them to an associated one of the plurality of connectors; (ii) memory for storing a communication mapping for identifying a respective one of the plurality of connectors to be used for each respective one of the messages in accordance with only an origin of the message; and (iii) a message depot for storing external correlator identifiers identifying the component applications, the external correlator identifiers received in notification messages from the at least one backend server in response to registration for notification messages from the component applications; wherein the component application is constructed as a series of metadata records using a structured definition language.