CartShield: Discount Blocker

CartShield: Discount Blocker is a Shopify app designed to help merchants protect margins and reduce coupon abuse by controlling discount code usage at checkout and on products. It offers flexible rule-based blocking for all codes, specific codes, products, collections, customer tags, or cart totals, plus an Allow List to whitelist approved codes and block the rest. The app also includes Smart Discounts that apply only to full-price items, avoiding products already on sale, and each rule can display a custom error message. Built on Shopify Functions, it emphasizes fast, instant performance for merchants who want tighter control over promotions.