Payment Token / Open Banking API integration

[cyberphone]

If the following is under consideration:
https://www.w3.org/blog/wpwg/2018/11/02/tpac-2018-recap/
For the second topic, Generic Payment Tokens, Adrian described the pitfalls of push payment flows: where the user’s bank initiates a payment (e.g., credit transfer) outside of the control of the merchant. Adrian offered an alternative flow where the party that initiates a pull payments returns a (“redeemable”) generic token through Payment Request API. The merchant can subsequently use the token to initiate the payment from the user’s bank. (I believe this is how direct debits work; please comment below if I am mistaken.) Adrian described a vision where merchants would declare through Payment Request API “I accept the generic token payload from the following networks,” and this would enable payment handlers to innovate and support different payment networks.

Implementation using Open Banking APIs
Although Payment Tokens would be great, they still need integration support in banks (or PSPs) to work. Since my Saturn (#42 (comment)) project is quite similar, the same kind of interface may be usable:

That is, reusing the interfaces banks in Europe are forced to build seems like a possibility. Note that in this particular case the Open Banking client is not a TTP but a local service.

The "wallet" shown in the picture could also be a W3C PaymentHandler.

[cyberphone]

I'm currently performing a PoC implementation:
https://github.com/cyberphone/swedbank-psd2-saturn
The initial results seem quite promising.