Taking the sibling commentor's analogy to mailto: links further: Imagine "digital wallet" apps, that would register themselves for the payto: scheme at the OS

Taking the sibling commentor's analogy to mailto: links further: Imagine "digital wallet" apps, that would register themselves for the payto: scheme at the OS level — just like web browser apps are registered openers for the http: scheme, or like email client apps are registered openers for the mailto: scheme. (I mean, you don't actually have to imagine them, they already exist. Apple Wallet is a "digital wallet app" on iOS. Native-app crypto wallets are "digital wallet apps." Paypal's mobile app is a "digital wallet app." None of them register for payto:, but they all could.) Now imagine that, like web browsers or email clients, every OS default-installed its own minimal first-party wallet app, so that it had something to fire up in response to a click on a payto: link, if you didn't have any other piece of software installed. Think "Outlook Express." Like with web browsers or email clients, you could install your own wallet apps, and then choose which one to make the default for the payto: scheme. There could be single-service wallet apps (created by your bank; by Visa/Mastercard/etc.; by Paypal/Venmo/etc.), and multi-service wallet apps (created by bigcorps and ISVs); just like there are single-service email apps (the "native Gmail client" kind of apps), and multi-service email apps. If you had multiple equal-priority scheme associations for payto:, your OS would pop a menu to ask you which app you want to use to open the link, just like it pops a menu when you go to open a file and there isn't a clear default association. The apps themselves would be free to ask more questions (or not) upon being intent-opened. If you click a mailto: link, then some email apps, when configured with multiple accounts, ask you which account you want to send the email as; others don't, but instead just let you switch the "From" field between your accounts, and do all the book-keeping to move the draft email between services, etc., in response. Same idea here.