We would like to build a shopify app which would create external one page checkout process for any merchant. We would like to give the merchant following features:
1. Payment gateway (Stripe, Square, PayPal etc.)
2. Instead of Shopify checkout our app should handle the payment page that would be a single page checkout.
3. Thank you page.
In beginning we would like to only these features.
1. Can we do this via public app so any customer can use our app?
2. Is there any specific security protocols we should have to handle in the app?
3. Do we need to go with Shopify APP Bridge or not?