The sections that follow describe some technologies that allow you to deploy ILE programs and service programs as web services. For each technology, there is a high-level introduction that is followed by information about whether there is support for SOAP or REST web services, in addition to where you can obtain more detailed information.
But before you get into the details of the various technologies, there is an important point to emphasize when implementing web services, and that is the characteristics of a web service.
When you create a web service on IBM i, most often you are attempting to provide some business logic to an interface outside your core application. Because you are dealing with an ILE or services program, there are some important concepts about that ILE program that must be considered.
Let's compare the traditional, monolithic model of creating applications to how web services are implemented.
As you can see, it is important that you understand that web services should be coded as granularly as possible, with no dependence on state information. Web service requests can come from anywhere and, when the documented interface is followed, the implementation can change as frequently as you want.