1. A mobile device comprising: a wireless transceiver configured to communicate with a developer exchange system over a wireless communications medium; a processor; and a non-transitory computer-readable medium storing instructions for execution on the processor, wherein the instructions include downloading and installing a first application from a digital distribution platform, and wherein the instructions include, in response to a user of the mobile device navigating to a state of the first application: instantiating the state from a first state template of the first application: selecting a first function module identifier from a plurality of predetermined function module identifiers, wherein each of the plurality of predetermined function module identifiers corresponds to a first function offered by the first state template, wherein the plurality of predetermined function module identifiers and an associated rank ordering are predetermined by a consuming developer of the first application before providing the first application to the digital distribution platform, and wherein in a first operating mode the selecting is based on a highest-ranked function module identifier in the rank ordering; selectively presenting a user interface to the user of the mobile device, wherein: the user interface allows the user to activate a second operating mode; the user interface allows the user to identify one of the plurality of predetermined function module identifiers; in the second operating mode, the selecting sets the user-identified function module identifier as the first function module identifier; and presenting the user interface is disabled based on a setting specified by the consuming developer; transmitting a function module request to the developer exchange system using the wireless transceiver, wherein the function module request includes the first function module identifier, which uniquely identifies a first function module, wherein the first function module was provided by one of a plurality of producing developers to the developer exchange system prior to the function module request being transmitted; receiving, via the wireless transceiver, the first function module from the developer exchange system; storing the first function module; executing the first function module; and presenting display data generated by execution of the first function module, wherein the display data is presented in an area reserved for the first function by the first state template.