The challenge
Digital coupons only work if the till in the shop accepts them: the app, the website and the point-of-sale systems have to agree on every coupon.
What we built
Native Android and iOS apps; a custom WordPress theme exposing a REST API on coop.hu; Python services for push notifications (APNs and FCM) and a TCP server that validates and redeems coupons at the tills; and a regular coupon and statistics data exchange with COOP.