Check out How to authenticate your iOS app using the Spotify iOS SDK and the SFSafariViewController by JR. Here is an excerpt:
To help me understand all the moving pieces of the Spotify iOS SDK I created this picture here showing how to setup authentication for a basic ViewController app.
Spotify App
First you need to create a Spotify application and set your clientID, redirect URI, the application bundle id of your…
The full article is available here.