How to execute the script only after receiving the payment?

Question

Payment systems

Good evening. please tell me how to implement the following task. You need to execute the script only after the user makes a payment. Something like how Internet providers work, you paid for the service, you were connected, regardless of the time of day. Somehow everything is done automatically and within a minute or two you are already with the Internet)). Who faced a similar task prompt in what direction to search.

Answer 1

search in direction
push URL
callback URL