How to combine use of payment processor with firebase or Auth0 login?

Question

I am new in the software development world. I have built a C# application that will require to keep track of user progress on a certain task and possibly integration of payment processor. I have seen Auth0 implementation requirements and I am able to implement it on my app. But the problem is- Auth0 gives user token and basic information like names on its example app, but what should I do with these data?

To keep track of user progress, I will need to implement a way to store data on a server probably in firebase. But should I use that Auth0 information to create a new users and update their progress? I don't know how to use token to create a user on firebase or at least to keep track of within the app.

Please give me a direction on how should I create and keep track of users with Auth0 given tokens or other information? Can I use Auth0 tokens to identify the user without using a server like a firebase?

Or is there a better way of combining these? Like firebase login with user creation? But how do I add a payment processor then? How the payment processor will combine the firebase user database and can process payment to the right user?

I have no idea about this and posting on different sites gave me no answer, so posting on the best possible site for this. Any information would help.

Answer 1

You can use the user_id from auth0 to retrieve the relevant info from your database.

Typically, the user will log in, the token will be issued from auth0, validate the token, then use the sub claim (the auth0 user id) to store and access data in your user db. This id can act as the connection between your db and auth0's database.