There is one other tool I want to talk to you about that (while extremely minor), is actually a really big deal. The JSONView Chrome extension is a very small plugin that will instantly convert any JSONView directly into a more usable JSON tree via the browser (exactly like in Postman Client). Here is an example of pointing to a URL that returns JSON from Chrome before JSONView is installed:

Here is that same URL after JSONView has been installed:

You should install the JSONView Google Chrome extension the same way you installed Postman REST Client: access the Chrome Web Store and perform a search for JSONView.

Now that you have the tools to be able to easily work with and test API endpoints, let's take a look at writing your own and handling the different request types.