Hi, I'm David, one of the engineers at Ribbon.
If you use any payment gateway, you need to send the full credit card number from the client so the gateway can return a token that identifies the card in their vault.
You can do the same and write some JS to get the first 6 numbers and send a GET request to our API without compromising security. The BIN (first 6 numbers of credit cards) is not considered the primary account number so it's safe to send (and even store).