11. Back-end
The back-end includes all the services or data offered by the online part of an application. Most applications require back-end functionality. These services or data may be core features or simply auxiliary ones, such as gathering analytics about app usage.
Structure of a back-end.
Source: Javier Salvador (Original image) License: CC BY-NC-ND 4.0
Since a back-end always requires an Internet connection, we must have the following permission in the manifest.xml of the app:
<uses-permission android:name=”android.permission.INTERNET”/>
If we use third-party back-ends such as Firebase, it will not be necessary to include this permission in our manifest.xml file. Instead, the permission will be included in the library that Gradle downloads so that we can communicate with the back-end.