The Challenge
Chamelo Eyewear needed a promotional discount for Valentine's that was value-based: 50% off the second-most expensive item in the cart, with optional free shipping — all running automatically at checkout without a backend.
The Approach
Designed an extension-only Shopify app using a Rust Shopify Function (WebAssembly) for cart logic and an Admin UI extension for merchant configuration. Mapped BOGO rules: expand by quantity, sort by unit price descending, apply 50% to the unit at index 1.
The Solution
Built a Shopify extension-only app with a value-based BOGO: 50% off one unit — the second-most expensive by unit price. Supports optional 100% off first delivery (free shipping). Merchants create the discount in Settings → Discounts and configure title, dates, and Product/Shipping classes; the function runs at checkout with no code required.
The Result
Delivered a zero-infrastructure discount that applies automatically at checkout. Clear BOGO logic (e.g. 2× $300, 1× $200 → one $300 unit gets 50% off) and optional free shipping, all configurable from Shopify Admin.