1. A method, comprising: receiving, by a host mobile device, a service-creation application; presenting, by the host mobile device and via the service-creation application, a user interface to define a service enabling the host mobile device to act as a web server to provide services to paired client mobile devices; soliciting, via the service-creation application and from a user, functional specifications of the service; obtaining, by the host mobile device, executable code for implementing the functional specifications of the service; storing, in a memory of the host mobile device, a service-engine for hosting the service, wherein the service-engine provides the service based on the executable code; announcing, by the host mobile device, availability of the service; receiving, by the host mobile device and in response to the announcing, a registration request from one of the client mobile devices; validating, by the host mobile device, the registration request; providing, by the host mobile device and to the one of the client mobile devices, the service via the service-engine, wherein the service adds a functionality to the one of the client mobile devices; detecting, by the host mobile device, a handoff to a cellular coverage area that cannot support the service; and providing, by the host mobile device and to the one of the client mobile devices a service interruption announcement.