When you create a synchronous listener notification (Apache Kafka or Confluent Kafka), Adapter for Apache Kafka creates the following document types:

At run time the listener notification invokes the service configured in the listener notification and passes the specified Request document. The configured service returns the Reply document to Adapter for Apache Kafka. The listener notification waits until the service has finished processing the message before it initiates the processing the next message. A synchronous listener notification does not publish a document.

For more information about specifying the execution modes for synchronous listener notifications, see Configuring a Synchronous Apache Kafka Listener Notification and Configuring a Synchronous Confluent Kafka Listener Notification.