I would like to create an application that will allow me to whitelist only certain merchants for a credit card. I think this can be accomplished with the Visa Transaction Controls, but does it require that I also work with the issuing bank? I would like to have a user opt-in for this service via any Visa based card, without having to go through the bank directly.
You can only block the Merchant Category Code. VTC is only available for Issuer bank and independent developer who are sponsored by Issuing bank. For more inforamtion on VTC please review the documentation at this link https://developer.visa.com/capabilities/vctc/docs