It is a third party that allows merchants to accept a wide variety of payments through a single channel.
The PSP works with acquiring banks (providers) to manage the entire transaction process from start to finish.
This means that the PSP is responsible from the moment a customer inputs their credit card details, to the moment the funds appear in the merchant’s bank account.

PSPs work with acquiring banks (also known as “providers”) to manage the entire payment process, from beginning to end. In practice, it looks like this: