What happens if you make payment multiple times with the same merchantPaymentId?
In what units merchantPaymentId needs to be unique?
Is it allowed to change the amount of continuous payment in the middle of a contract?
The "OP_OUT_OF_SCOPE" error occurs when using the Create a QR Code API in PreAuth & Capture. How can I handle it?
Is it possible to test a payment limit?
Tell me how to handle the error that occurs when switching to the production environment (UNAUTHORIZED).
Does PayPay provide an API health check function?
What is the best way to implement Cashback?
Can I cancel my cashback?
How long can I cancel my cashback?