Wireless data message optimization for messages sent between a wireless device and a server that provides a service that the wireless device is authorized to access is provided using an application gateway that serves as a proxy between the wireless device and the server. The application gateway maps optimized service request messages generated by the wireless device to a service request message format expected by the server, and maps response messages generated by the server to an optimized response message format expected by the wireless device. The optimized message format is flattened by removing unnecessary message structure, eliminates unnecessary message fields, and uses default and enumeration encoding to reduce optimized message size.