Zupli replaces the default cart with a customizable slide cart for running cart-based offers and upsell campaigns.Merchants can set up gift with purchase, BXGY offers, tiered rewards, progress bars, and in-cart upsells using real inventory.Zupli uses Shopify Functions, avoids adding zero-value products, and is built to remain stable during traffic spikes.Designed for performance, it works across mobile and desktop without interfering with checkout.