Re: [webpayments] How are cloud-based payment instruments supported? (#16)

I want to attempt to close the issue by referring to the proposed new terminology and therefor place payment instruments in a different place in this flow.

Here is a slight variation of @msporny 's flow above:

 1. `navigator.payments.requestPayment()` is called, generating a Promise that the merchant waits to be resolved.
  1. A pop-up opens (rendered by the UA who is acting as payment mediator in this context), user selects the payment app they want to use.
 1. A new dialogue window opens and renders the content fetched via a POST to the payment app's request endpoint (with the original payment reuqest object passed to the browser API as the request payload, trimmed to exclude content that is not appropriate for this app).
 1. The payment app processes the payment request, calls `navigator.payments.respond(...)`, which closes the dialogue and relays the payment response back to the UA which fulfills the promise in the merchant website's window.

As you can see, unless the UA provides a way for the payment app to be built-into the UA as an extension or similar (or provides a bridge to a native app - as may be the case for mobile platforms) all payment apps are cloud-based and certainly they will have out of band comms with their publisher or processors to perform a variety of functions like authenticating the user, getting tokens or similar.

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/webpayments/issues/16#issuecomment-163179406