It's important to remember that a REST web service is by definition a stateless service, this will imply some requirements in the way we will test things and deal with the information we need to POST or GET.

The big step forward that Yii made with version 2 can be seen in the built-in REST classes that provide an immediate solution once provided by third-party implementations.

This means we'll have to introduce several changes to what we've achieved so far; the REST part of the application will be developed as a separate module, which will give us the ability to extend it and contain its logic. Because of this, the routes will be rearranged appropriately as well.

Before seeing what the Yii REST functionality is capable of doing, we'll need to first have a quick look at modules in Yii, which we will use to develop our API to be tested.