An event processing system is disclosed that processes events of an event stream and performs the recovery of events during system failure. The recovery of events is performed by generating output sequence numbers for each deterministic output event generated by the event processing system. In an embodiment, the event processing system determines a current output sequence number of a most recently transmitted output event in a output stream of events, a last output sequence number of an output event corresponding to a most recently processed batch of input events and determines a set of one or more output events of the output stream to be transmitted based on the current sequence number and the last output sequence number. The event processing system then transmits the output events related to the application.