American Express (AMEX) is one of the three largest credit card companies in the world. And that is exactly why it is a widely used online and offline payment method. The American Express credit card is popular because of the extensive service and the many extras AMEX offers (i.e. the loyalty program). On top of that, consumers can choose between a Green Card, Gold Card or the Platinum Card.
In addition to Visa and Mastercard, you can also add AMEX as a payment method to your webshop via Pay. With American Express your customer can make purchases and pay for them afterwards. The amount is not debited directly from the account, but billed at a later time by the credit card company by means of an invoice to the buyer (your customer).