The ReplyTo field is an optional field in the message header. It contains the message's reply address (or end-point reference). Applications should be designed to populate this field if necessary. (Because the JBoss Enterprise SOA Platform's recommended interaction pattern is based on a one-way message exchange, messages may not receive responses automatically: it is application-dependent as to whether or not a sender expects a response.)

If a response is required and the ReplyTo field has not been set, the JBoss Enterprise SOA Platform can automatically populate it based on default values for each type of transport. (Note that to use some of these ReplyTo defaults requires system administrators to specifically configure the JBoss Enterprise Service Bus' behaviour.)