Interchange is a fee that the card brands (Visa & MasterCard) impose on the merchant and pay to the card issuing banks.

Do you know what you are paying for credit card transaction processing? Unfortunately, statements from most payment processors don't always tell the full story and often leave out and/or bundle hidden costs which can make it almost impossible for merchants to keep track of what they are paying for; especially in processing bank card transactions from VISA and MasterCard.