Merchants including Walmart, Starbucks, Postmates and Verizon are connected to the Knot card-on-file management platform to automatically receive changes when a cardholder adds a new debit or credit card as their default payment card. Knot sells an SDK to card issuers. They can implement the card-on-file management service on their mobile app or website. Cardholders opt in through their banking app if they want to instantly update Knot-supported merchants with new credit, debit or prepaid card details. This saves them from having to manually input new information. Knot receives all the c...