@stefanclark What you are trying to do is not possible. Stripe’s npm is meant only for backend use.
On stripe’s example checkout.html see line 7 ](<scriptsrc=“https://js.stripe.com/v3/”>) [**<script**](<scriptsrc=“https://js.stripe.com/v3/”>) [***src***](<scriptsrc=“https://js.stripe.com/v3/”>) [**="https://js.stripe.com/v3/"**](<scriptsrc=“https://js.stripe.com/v3/”>) [**></script>**](<scriptsrc=“https://js.stripe.com/v3/”>) [
This imports the stripe script from a url, this is not the stripe npm.
From Stripe: " Stripe Checkout relies on Stripe.js, Stripe’s foundational JavaScript library for collecting sensitive payment information and advanced fraud detection. Always load Stripe.js from js.stripe.com to remain compliant. Do not include the script in a bundle or host it yourself. "
A script import like this is only possible on custom webpages where you can edit write html, not on wix.
If you are looking for 3d secure implementation see this post