Looking got an app developer to create a custom app for a client.

Looking got an app developer to create a custom app for a client. Platform: Shopify... Stack, React js, Node Goals: Combine 2 coupons into a single coupon. ex. 10% off order / Free shipping Shipping needs to be controlled in what region this is allowed. ex. All of us ( exclude Hawaii, Alaska ) Code must be within Shopify so they can work with my affiliate program (GoAffPro