WebSphere Message Broker (also known as "WebSphere MQ Message Broker") is IBM's information broker from the WebSphere product family. It allows business data and information in the form of messages to flow between disparate applications across multiple hardware and software platforms. Business rules can be applied to the data flowing through the message broker to route, store, retrieve, and transform the information.
WebSphere Message Broker can be run on a wide range of Operating Systems designed for the Server environment, including Windows 2003, Linux on various architectures and various Unix flavours - AIX, Solaris and z/OS.
WebSphere Message Broker is distributed using Java technology, as such it is cross platform to a certain extent, it has been released in two versions, a multi-platform release which compiles on all OSs, except z/OS, and a z/OS specific Binary release.