A method, system, and computer program product for improving a distributed application using diagnostic heartbeating are provided in the illustrative embodiments. An application, executing using a processor and a memory in a first data processing system, sends a registration to a component in the first data processing system. The registration requests state information for a set of member components in a distributed domain. After the application sends the registration to the component, the application receives the state information from the component. The state information includes current status and diagnostic information relating to the set of member components obtained from diagnostic attributes of diagnostic heartbeat packets received by the component. A diagnostic heartbeat packet is a packet comprising a header, a set of heartbeat parameters, and a set of diagnostic attributes.