Various topologies of a quality of service application controller and related techniques to optimize the communications performance an application executing on a device participating in a communications environment are disclosed. The communications environment may include a cellular network, an unlicensed spectrum network, or a combination of the two. The quality of service application controller observes one or more key performance indicators of the communications network, and retrieves a policy from a policy store specific to the application. The quality of service application controller then modifies the execution of the application and/or the configurable aspects of the communications environment to optimize the communications performance of the application. For example, the application's data throughput may be increased, the power draw of the application may be minimized, data requested by the application may be minimized, or the apparent response time of the application's response to a web service may be minimized.