Being able to efficiently send and receive JSON data from our .NET Core Controllers is probably the most important requirement for our SPA. We chose to do that using the brand new Angular HttpClient, first introduced in Angular 4.3.0-RC.0, which is among the best answers the framework can give to get the job done. For this very reason, we will use it a lot throughout the whole book; however, before doing that, it might be advisable to properly understand what it is, why is it better than the former implementation, and how to properly implement it.