Skip to main content
Public checkout helper. No seller session. Rate limited (20 requests per client window). Seller CRUD lives at /api/coupons and /api/coupons/{couponId} with manageCoupons.

​
Usage

Call from checkout UI before applying a discount. Embed can also pass couponCode into create-checkout so Join Markt applies it when opening the invoice.

​
Errors

Invalid / expired / ineligible codes return a 4xx JSON { error } (or domain payload). Do not invent client-side discount math that disagrees with the server.