Getting Subscriber List from Server

You would need to collect and store your credentials in the very same database (or in a flat file if you prefer)

Your token will only be valid for abound 4 hours (generally speakling) but it will come with a refresh token you can use to regenerate the access token.

This nodeJS example I wrote t’other day, https://github.com/BarryCarlyon/twitch_misc/tree/master/examples/moderator_dashboard descibes a method to collect, store and regenerate a broadcasters token for use by a backend service. (Example illistrates a “moderator dashboard” example and a “subscribers portal” example). Which should illustrate a suitable workflow to do what you are after.