A computing device may send a request to a telephony server over a network to initiate a call with a telephony device, and may output for display a graphical user interface (GUI). A first process executing at the computing device may provide a first one or more call controls in the GUI for controlling the call. A second process executing at the computing device may provide a second one or more call controls in the GUI for controlling the call. In response to receiving user input indicative of a selection of a call control from the first one or more call controls to perform an action for the call, the second process may update the second one or more call controls based at least in part on the action to be performed.