Hardcoded apps
App with Servcie dns linked directly into the app, all customisation settings configured at the time of app compiling of the app.
Api/Panel based apps
App is paired with a panel
The app panel dns is added to the app itself where is calls to the panel for most if not all configurations that are set by the panel
This includes one or more service dns's
The app still communicates directly with the service once the data is received from the panel
There is a slight exception
A few apps do route through the app panel, I can not remember which ones exactly do this.