Discount codes are not automatically applied when paying with any of the express checkout payment providers (Apple Pay, Google Pay, PayPal, Amazon Pay). What can I do?

Shopify doesn’t allow you to apply discount codes before the checkout page, and when your customers add their payment info to PayPal and then go to checkout the discount is not transferred to the checkout. This feature has been requested from Shopify by many users for a long time (you can see here) but still, there isn’t any solution for it.

Is there anything Fast Bundle can do about it?

There is a discount application method called "Shopify Functions".

It is possible that this discount application method can integrate the Fast Bundle discount with mentioned payment methods.

We say it by uncertainty because it depends on your theme and shop's settings and it may work for you or not. It should be checked.

Feel free to contact Fast Bundle support (support@fastbundle.co) for any questions or customizations.