Re: [browser-payment-api] Redefinition of BasicCardResponse to address Issue 9 (#25)

I'm less concerned about the format and more that we don't spread the idea that "Visa" is a good example of payment method identifier. That's an important point to come to consensus on (we started drilling into it late in the afternoon at the F2F).

Payment Method Identifiers (PMI) serve 2 purposes so their design must consider both:
 1. To indicate request and response message format for the interactions between the website, browser and payment app. A single specification of these message formats could apply to a set of many payment method identifiers (as is evidenced in this spec).
 1. To indicate specifically which underlying payment instruments (brands) are supported by the website. i.e. A merchant can process card payments but might not accept all card brands.

>From an architectural perspective one could think of PMIs as foreign keys that provide a many-to-many link between payment instruments and the messaging protocols that can be used to pass payment data back and forth for those instruments.

I can imagine people minting new PMIs for two reasons:
 1. They have developed a new messaging protocol and have documented it in a specification like this one and need to provide PMIs that link payment instruments that can be used with this protocol to the protocol.
 1. They have a payment instrument that can be used with an existing messaging protocol and so they mint a PMI that they get added to the list of supported PMIs in the existing protocol's spec.

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/browser-payment-api/pull/25#issuecomment-195365823