A message broker is, like message queuing and message passing, a variant of the messages-oriented middleware (MOM). The advantage of message broker in comparison to the MOM reside in the conversion of data types which allows it to run in heterogeneous environments. Netsize Active Gateway offers two ways to store information (in memory or in a folder) and use a dynamic data structure that is comprehensible by every platforms.

A logical hub that copies and resends messages to one or more destinations. As a value-adding third party between information sources and information consumers, it can complement a service-oriented architecture (SOA). Like an SOA, a broker is a design abstraction that may be implemented using component software for some or all of the connections. The interface from a message broker to the application may use an object request broker (ORB) or object transaction monitor (OTM); a request to the message broker may be implemented as a series of method calls to participating components. See SOA, ORB and OTM.

A key component of EAI, a message broker is an intelligent intermediary that directs the flow of messages between applications, which become sources and consumers of information. Message brokers provide a very flexible communications backbone and provide such services as data transformation, message routing and message warehousing.

IBM MQSeries is the best known and perhaps the de-facto standard message handling system.

a physical component that handles the communication between applications