With the coming of new web development patterns there is the need for new development techniques. As we said in the previous chapters, future web applications are composed by complex clients and complex servers. This approach can't rely on simple HTTP request that are manually handled by programmers, due to the complexity of this process, for the client-server interaction.

The scenario depicted by new web applications is composed by servers that offer a service in the form of an API and clients that consume that service using that interface. This makes clear the need for a Remote Procedure Call framework that makes the use of a server's service easy and fast for clients programmers.

This way is well known, and, as we saw, tools like GWT already provide RPC mechanisms.

The problem is that GWT (that is our reference tool in this text), provide only a Java Servlet backhand. Our goal is to build a simple RPC framework for a more cheaply PHP backhand. This effort is done to provide a framework to build a simple application (In the next chapter!), to give a real sample of the possibilities of this new development approach.