Design a Credit Card Processing System

To clarify: what level are we implementing. For e.g, are we using Stripe?

How will you handle the case where the payment is successful, how will you mark the payment as completed?

How will you handle payment failures?

How do you ensure that a payment doesn't get processed twice?

How do we handle global payments?

How do you conduct a large number of transactions?

How do you handle a burst of payments?