Database & Payment Server

I am looking for an example iOS application developing where it shows the implementation of a BaaS (Back-end as a Service). The back-end should include a database and payment system. The database should be able to store custom information that the user would enter in the app, such as passwords, usernames, emails, phone numbers etc. It would also need to be editable by the user and me, it should store other information that I myself can enter and then read only from the application. The payment system should be able to read user account information and upon request make a payment for physical good, therefore In-app purchases is no allowed, I suggest something like Braintree or Stripe. The payment should be made to custom accounts that would need to be stored somewhere. This is for a large scale application and so it should be capable of handling thousands of users at the same time.