#kashey-applepay-iframe
olive ibex
clever carbon
@twilit lotus does our doc solve your ask? https://stripe.com/docs/stripe-js/elements/payment-request-button?client=html#html-js-testing we cover the iframe part and say
When using an iframe, its origin must match the top-level origin (except for Safari 17 when specifying allow="payment" attribute). Two pages have the same origin if the protocol, host (full domain name), and port (if specified) are the same for both pages.