A data subscription system provides emergency event data to receiving systems. The data subscription system includes an event emitter and a distribution module. The event emitter receives event data describing an event in a computer-aided dispatch (CAD) system; the event is related to an emergency call. The event emitter identifies a subscription subscribed to the event based on a tenant identifier identifying a CAD tenant associated with the event, and adds a data message with the event data to a queue for the identified subscription. The distribution module retrieves the data message from the queue, transforms the data message based on one or more filtering or formatting rules, and transmits the transformed data message to a receiving system associated with the subscription.