Middleware, which is quickly becoming synonymous with enterprise applications integration (EAI), is software that is invisible to the user. It takes two or more different applications and makes them work seamlessly together. This is accomplished by placing middleware between layers of software to make the layers below and on the sides work with each other (Figure 1). On that broad definition, middleware could be almost any software in a layered software stack. Further, middleware is a continually evolving term. Since much of the software business is driven through the perceptions of the “hottest” current technologies, many companies are giving their software the name “middleware” because it is popular.

Middleware, or EAI, products enable information to be shared in a seamless real-time fashion across multiple functional departments, geographies and applications. Benefits include better customer service, accurate planning and forecasting, and reduced manual re-entry and associated data inaccuracies.

Middleware is essential to migrating mainframe applications to client/server applications, or to Java or internet-protocol based applications, and to providing for communication across heterogeneous platforms. This technology began to evolve during the 1990s to provide for interoperability in support of the move to client/server architectures.1[1] There are two primary applications for middleware using any of the above middleware initiatives: Computer Telephony and Software Interfaces such as via Java based middleware applications. In this discussion of middleware, we will explore both uses.