Quote from: BitCheques on May 24, 2022, 12:30:18 PM

I like the durability of credit cards, but in the target market, vendors are not equipped for any electronic equipment. The bolt card seems to require a companion electronic wallet.

I find this a better path, although, yes, you have to do proper research here too.
I think that you can easily require a smartphone with NFC, it may be easier for everybody. I don't know though if only the merchant has to have the hardware, or will the customer have to have it too (in order to avoid troubles).

Satochip based hardware wallet works on NFC and afaik it's open source. Although I can guess it's not 100% what you need, you may gather some knowledge also from taking a look there. Just an idea...