With Spotify Premium, where the music comes from?

[OlivierMoser]

I have question regarding the audio backend: Does it always go through youtube or it can come from spotify directly?
If I have a premium account, is it possible to play music with the highest quality of spotify?

[PabloSoage]

Thanks for the question!

By default, the audio doesn't come from Spotify. Rustify uses Spotify for your library, search, playlists and recommendations, and resolves each track to an audio source: YouTube via yt-dlp by default, with Invidious, Deezer and installable add-ons as alternatives (Settings → Audio). So in the default setup, having Premium doesn't change the audio quality.

There is an experimental mode that plays through Spotify's own web player inside the app (Settings → Audio). It comes in two variants, and they behave very differently:

• Mobile page: this one works — on phones, and on tablets since v3.7.4. It plays the track you pick. I've only been able to test it with a free account, so I can't say yet how it behaves with Premium.
• Desktop page: this one does not play. I looked into it closely for v3.7.4: Spotify's servers accept the play request but never send a track to the in-app browser, while the exact same request from desktop Chrome, with the same account, plays straight away. It looks like a deliberate restriction on browsers embedded in apps rather than a bug on our side, so I don't expect to be able to fix it.

On the highest-quality question: through the web player you get whatever Spotify's web player serves, and I haven't been able to verify what that is for a Premium account inside the app, so I'd rather not promise Spotify's top quality. If you have Premium and try the mobile mode, I'd really appreciate hearing how it goes!