Step back in time and think about the order of the Internet evolution. In the early Internet days, text-based content was king. Over time, Hypertext Transfer Protocol (HTTP) and Hypertext Markup Language (HTML) evolved to be rich enough to represent acceptable multimedia content. Further, the protocols and markup languages were easy enough that anyone could build and deploy a Web page. By this time, network bandwidth was still catching up to the content offered on the Internet.

Everyone has an answer to the question “What is a Web service?” but at least you can now see where Web services fit into the grand scheme of things and can settle on a definition of your own. Here, we define a Web service as a remotely accessible application component that listens for certain text-based requests, usually made over HTTP, and reacts to them. Web services might not return results in the same way, and what the request is for is irrelevant.