Saving user data from Spotify API - spotify

I'm currently toying around with the Spotify api to create a mobile app that "matches" people based on their top artists, tracks, and genres.
For this, I need to save the user data (top 50 tracks and artists, from the Personalization API) and fetch them back as needed.
So basically if User A signed in the app with its Spotify account, its data is saved in my DB.
After that, if User B wants to see if he is a match with User A the server will provide information about both User A and User B, for instance, what artist they both like.
There is this point in the TOS about user data:
"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"
As far as I understand, it's ok to save the user data in an external server/DB as long as I delete that data as soon as the user logs out from my app, is that right?
I'm asking because at the same time there is this restriction stated in the TOS:
"Do not transfer Spotify Content to unauthorized third parties, including (i) directly or indirectly transferring any data (including aggregate, anonymous or derivative data) received from Spotify to, or use such data in connection with, any ad network, ad exchange, data broker, or other advertising or monetization-related toolset, even if a user consents to such transfer or use; or (ii) to another music service that competes with Spotify or the Spotify Service."

Related

How would I check a user of my website is a subscriber of a youtube channel?

I am trying to create a website that checks if the current logged-in user is subscribed to a specific youtube channel. This is meant to restrict the user if they haven't yet. Is something like this even possible?
You would need the user to login via google identity services to be able to access data like that via the api. The api gives you access to the channels the user is subscribed to if the user allows this

Get user ID - WebAPI Spotify (Spotipy)

my question
is possible get a user id in any way? I would search a user from his name and print his recently artist played
Thanks
This is not possible due to Spotify's Web API has no endpoint where you can fetch user ids by their names.
What you can do is creating an application where a specific user can login using Spotify. Afterwards you can use this endpoint in order to retrieve the recently played tracks of that exact user. The track object in the response will hold the artist as well.

Is it possible to check whether a user has access to Spotify for Artists for a specific artist?

I am trying to automatically verify that a user is a particular Spotify artist (or at least on the artist's team). The problem is that an artist and a user are different. Spotify's authentication API deals with user accounts. However, user accounts are used to access Spotify for Artists and are internally verified by Spotify.
Therefore, it looks like I just need some way to check whether the user can access the artist. Is there any API or other way to check that a particular authenticated user is tied to a Spotify for Artists account?

Restrictions on accessing users public playlists

I am thinking of doing a web app that uses keywords to query Spotify web API for public user playlists, and then do an online mashup with my own music retrieval system. Is it allowed? Can the playlist names and tracks be cached for the purpose of categorization.
I read through the Terms of Use and saw this:
"Do not improperly access, alter or store the Spotify Service or Spotify Content, including (i) using any robot, spider, site search/retrieval application, or other tool to retrieve, duplicate, or index any portion of the Spotify Service or Spotify Content (which includes playlist data) or collect information about Spotify users for any unauthorized purpose;"
Paul Lamere does something similar with Playlist Miner: https://github.com/plamere/playlistminer. But he is an EchoNest employee.

Get list or count of registered users for application

Using Instagram's API, is there any way to request a list or count of an application's registered users?
Instagram's real-time subscriptions can send notifications whenever a registered user posts to their feed, but I haven't found a way to get a list of those users, or even a count. This is easy enough to store server-side, but seems like something which should be discoverable.
Your Question
Using Instagram's API, is there any way to request a list of an application's registered users?
A quick search yielded no results for such a functionality. This make sense, though, since Instagram wouldn't want to open up all its users to any app designer.
Your App
If you want the number of users using your app, then you can easily track this yourself.
Instagram App
As mentioned before, Instagram probably won't provide even basic count information about its registered users. Presumably, this is valuable information.
Your Example
Instagram's real-time subscriptions can send notifications whenever a registered user posts to their feed...
This is true, but with very limited scope. The subscriptions below are based on users who are using your app or other simple criteria such as tags or geographic data.
Users: receive notifications when users who have registered with your application post new photos.
Tags: receive notifications when a new photo is tagged with tags of your choosing
Locations: receive notifications when new photos are posted and tagged with a specific location
Geographies: receive notifications when a new photos are posted in an arbitrary geographical location as defined by a center point
and radius
As far as I have found this far there is no IG API, however as already indicated you can keep track on your app. HOWEVER, what has not been pointed out is that you won't be made aware if users terminate their account or revoke your app so the count's might be a little off. (or worse if you didnt start keeping track since the public launch of your app)
You could test on a periodic basis if you still have access, but that would require additional code, and a lot of API calls if you app has a lot of users. I hope that IG will add this function at some point.

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