A method and computer for responding to an assistance request message. An assistance request message from a requester mobile device associated with a requester is received at a response computer. The assistance request message includes at least one input parameter. A responder is determined, from multiple potential responders, to respond to the assistance request message. The responder is associated with responder data corresponding to the at least one input parameter. An availability inquiry message to a responder device associated with the responder is transmitted. A response to the availability inquiry message is received from the responder device. When the response to the availability inquiry message indicates that the responder is available to respond to the assistance request message, the requester mobile device is notified that the responder is available.