As far as I understand, Apple Pay can be used with any EMV contactless card reader and it works with all four major card networks (perhaps more outside the US).

As far as I understand, Apple Pay can be used with any EMV contactless card reader and it works with all four major card networks (perhaps more outside the US). From the merchant's perspective, it's the same as someone tapping their physical Visa/Mastercard/Discover/Amex at the terminal.