American Express has partnered with Knot (an Amex Ventures portfolio company) to launch a pilot test run of card of file at select merchants as Bloomingdale’s, Hilton and Macy’s. Cardholders that are included in the pilot are able to automatically add their ‘card-on-file’ at the participating merchants. This is the combination of two technologies:
Knot’s CardSwitcher, which lets customers change their payment methods easily with different merchants without the need to enter their Card.
American Express proprietary technology, which enables customers to share their payment data securely with their permission
Can’t really see these sorts of things taking off if they are restricted to a single payment network/card issuer.