What is the best Paypal tool to use for auto-accepting payments on an event?

Question

PHP

There is a site that monitors certain events (the appearance of goods in access). It is necessary to withdraw money from the client's Paypal every time an event occurs. It's not entirely obvious which Paypal tool to use for this. Events do not have a defined periodicity, so RecurringPayments are not suitable. DoReferenceTransaction seems to fit, but why does the documentation say that credit card information is required? I don't want to touch credit cards: everything must go through Paypal exclusively. It is also not entirely clear how to authorize a person to further use DoReferenceTransaction? After all, it is probably necessary to first carry it through some kind of procedure, it should look something like connecting the Payment Method to Upwork. Maybe something else is used there?
Thanks a lot in advance for any hint/guide.

Answer 1

(Required) A valid transaction ID from a previous purchase, such as a credit card charge using the DoDirectPayment API, or a valid billing agreement ID . Billing agreements are valid until the agreement is canceled by the buyer; whereas, transaction IDs are valid for 730 days from the transaction date.

https://developer.paypal.com/docs/classic/express-...
https://developer.paypal.com/docs/classic/express-...