Other emulators may use a different IP address, for instance, Genymotion uses 10.0.3.2. The default Android emulators use 10.0.2.2 for this communication instead of localhost.
The first thing is to understand that Android has a special IP address to communicate and loop back to the host machine. With a little “know how” you can now also debug your Android apps locally regardless if you developing on Visual Studio on Windows or Visual Studio for Mac. But we’ve got you, Android app developers, covered. However, this is not the case for Android debugging, because Android emulators have their own networking configuration whereas the iOS simulator uses the same network as the local machine. If you are using Visual Studio for Mac and debugging iOS applications you know it is as easy as running your web API locally and using localhost as the URL for web requests.
When developing mobile applications with a web API backend there is always a need to debug locally on your development machine.