Hi! I'm new to the Shopify app development ecosystem and am trying to figure out the simplest way to build out some additional discount functionality.
Currently, when the user gets to the checkout page, they have the option of entering a discount code for the order. If the code is valid, some amount will be deducted from the order total, and the user will pay the discounted price.
What I want instead: after the user enters a discount code, additional text appears on the checkout page asking the user if they would like to donate their discount to a charity that the merchant works with. There are radio buttons for "Yes" and "No", with an "Apply" button to confirm the user's choice. If the donation option is selected, the order updates to reflect the user paying the full order price, and the donation amount is added to the order as some kind of metadata.
I'm looking through the docs for Admin API, App proxies, and Shopify App Bridge, and I'm a bit confused as to where to begin. I'd also prefer for this to be a private app, but it sounds like it won't be possible to do that and also use app proxies (although perhaps I don't actually need them in the first place). Any pointers around which Shopify development tools would be best suited for building this out (from both a backend and frontend standpoint) would be greatly appreciated!
In general the Shopify Checkout is fairly immutable. The one exception is that Shopify Plus stores have access to Shopify Scripts and checkout.liquid which would be the only way to accomplish what you've described on the checkout page.
Hope this helps,