A handler service is a service that a process model step invokes when triggered by an event in the PIP process. For example, in the process model template, the Verify ACK step invokes the pub.estd.rosettaNet:verifyAcknowledgement service when the initiator receives a receipt acknowledgement (ACK) from the fulfiller.

In Designer, you create handler services by creating a new service for each event that you want to handle in a RosettaNet conversation.