I've been working on my Swift Playgrounds entry for WWDC 2018, and I've been wondering, is there a rule against using external APIs/SDKs? I've been trying to import music into the playground through some kind of MPMediaPicker, but that hasn't been working. Every time I try, I get a blank white screen. So, I was considering using some kind of SDK from Soundcloud or Spotify instead to let users import their own music. Is this allowed? If this isn't allowed, why would an MPMediaPicker not work in Swift Playgrounds?
Last I checked, it was a requirement by Apple that you had to own all the content on your playground.
Although the requirements for WWDC Scholarships change every year, you might find last years WWDC Scholarship Terms and Conditions helpful.