The publish-and-subscribe model is a specific type of message-based solution in which applications exchange messages (called documents in webMethods) through a third entity called Broker . In solutions based on this model, applications that produce information (publishers) send the information to the Broker entity and applications that require the information (subscribers) connect to the Broker and retrieve the information they need.

The Broker entity temporarily stores the documents that it receives from publishers in a message queue. Subscribers connect to the Broker entity and fetch documents from the queue. Depending on the application, a subscriber might publish a response after it retrieves and processes a message, but it is not required to do so.