Is it against TOS to save user id's in my own database for my web app that uses the Spotify API?

[Terrancehanlon]

I'm building this web app that is basically a social service to share spotify playlists. It's critical for me to able to have persistence of spotify data so other users can see other users playlists.

In order to do this (from what I brainstormed so far) is that if I save the users unique spotify ID into my own database that way I can use the API to get everything I need. 

I read through https://developer.spotify.com/terms/#iv and I from what I gathered it seems against TOS unless it's necessary to operate the application?

[Koyama_Ichisake]

It does not seem against the TOS to use spotify usernames, but it is against the TOS to save passwords and personal information.  If you are saving your own id, password, and personal information, then it is not against the TOS, just as long as you aren't sharing it.

[Alex357]

I had the same concern and unfortunately it seems that Spotify Content related to a Spotify user cannot be stored permanently into a database. At least, that's what I understood from the point 8, https://developer.spotify.com/terms/#iv section:

"Spotify user data can be cached only for operating your SDA. If a Spotify user logs out of your SDA or becomes inactive, you will delete any Spotify Content related to that user stored on your servers. To be clear, you are not permitted to store Spotify Content related to a Spotify user or otherwise request user data if a Spotify user is not using your SDA."

This is a major blocker for the implementation I wanted to make because it seems that I can store the user ids, into a database, just as long as the users are using my app.

If anyone could provide any other information regarding this aspect, it would be helpful.