From what I’ve seen, the main limitation for Apple Pay JS on a web page is that you need to use a SFafariViewController, which is what Capacitor’s In-App Browser generates.
My team’s main concern is that we might run into issues with protocol, because Apple requires https, and I gather it is not possible to force an app to use https:// instead of capacitor://, and can even lead to an app being banned if you try. But we’re not sure if the example linked to applies to using an in-app browser, that would essentially be opening a different webpage altogether.
Is it possible to setup a webpage that implements Apple Pay JS, open the page via an in-app browser, then direct users back to the app once payment is complete?