There is provided a service system, application platform, application design framework and method of providing a service over a hybrid network comprising at least one circuit-switched network and at least one packet-switched network connected via at least one gateway configured to provide necessary conversion to a video call passing between the packet-switched network and the circuit-switching network. The application design framework is configured to be located in the packet-switched network, to be operatively interfaced to the gateway and to enable development of one or more applications to be accommodated by said framework. The application framework is further configured to be capable of receiving a video call initiated by a video device from the circuit-switched network and transferred through the gateway and of further serving as an end-point of said video call; analyzing, at least, in-band information comprised in the received video call therefore recognizing user-related information; providing the recognized user-related information to one or more applications when accommodated by the framework; and, optionally, of handling one or more media streams in accordance with instructions by one or more applications when accommodated by the framework.