In this chapter, we briefly touched on Promises and how to verify our communication with the backend was secure. We explored communicating with our API using XMLHttpRequest in-depth and also discussed how to decouple our app from the API and instead allow the API responses to tell our app what it can do next. This means that as long as the client app respects the API contract, the underlying URIs, field names, templates, headers, and so on, can change and our code will execute without a problem.

At the end of the chapter, we addressed how our API handles authentication, and how tokens are converted from an intermediate form to a final form that the server will accept.

If you run our sample app on your device, you should see the output similar to the following screenshot:

In the next chapter, we'll cover handling application and network events, local storage options, encrypted storage options, and data caching and synchronization.