I would have liked to integrate Spotify, but as I also include “other streams” for the alarm sound, so it is not allowed:
Spotify Developer Terms of Use
Section IV: Restrictions
Spotify Content Restrictions
- Integration with Third Party Services. You shall not create any product or service by integrating the Spotify Platform, Spotify Service, or Spotify Content with (i) any non-interactive internet webcasting service or (ii) with streams from another service.
And:
The Android SDK is explicitly prohibited from use for in-car apps, re-streaming aka “listen together” apps, alarm tones, ring-tones, voice-assistants, and offline experiences for wearable or other devices.
Well then… no Spotify in the app.