Challenges
Managing Complex Cart and Promotional Behavior
Wonderskin's cart carries bundles, free gifts, promotional products, landing-page carts and upsells at the same time. Several gaps had appeared in how it handled them.
Internal product information was visible to customers in the cart. Anyone who opened /cart directly could change the quantity of a zero-value free-gift product, which defeats the point of a fixed free gift.
Discounted upsells stayed reachable after a customer left a landing-page cart and returned to the homepage, outside the journey they were designed for. The Shop the Look add-to-cart flow also needed cleanup. A timing issue was added to this point.
When a customer removed a qualifying product, the cart update could still be running when they clicked Checkout, so a free gift could briefly remain in checkout.
The cause sat between Shopify's asynchronous cart update, the UpCart cart drawer and the hand-off to checkout, which made it harder to trace than the visible problems.
Developer Dependent Discount Management
Wonderskin’s promotional discount rules lived in hardcoded storefront logic, so adjusting a promotion meant changing code. Wonderskin wanted more control over scripted discounts without ending that logic each time.
On the US and EU landing pages, offer discounts could also combine with other product discounts when they were not meant to.
Checkout and Customer Experience Gaps
Four unrelated gaps affected checkout and the account experience.
Wonderskin wanted a "You May Also Like" section in checkout that did not recommend products already in the customer's cart. Existing Skinsider members were still being shown the option to add a membership.
Lip Trio offer products were not carrying their promotional tags at product level, even though the order-level tags were correct. And the EU and UK checkout needed a clearer marketing-preference section that explained the choices and linked to the Privacy Policy.
Solution
Cart Behavior and Promotional Journey
Lucent Innovation removed the internal product information form the customer facing cart and cleaned up the shop the look add to cart flow.
The item then redirected /cart to /checkout. Customers can no longer open the cart page and change free gift quantities there.
On the checkout timing issue, Lucent's analysis confirmed that Shopify can still be processing a cart update when a customer clicks Checkout and that UpCart has no native way to block checkout during that window.
A custom checkout-disable mechanism was identified as the appropriate fix. It remains a recommendation.
Configurable Discount Management with Shopify Functions
The goal was to move promotional behavior out of hardcoded logic and into settings Wonderskin's team can adjust. Lucent built this on Shopify Functions, which let custom discount logic run inside Shopify's own checkout flow:
- The Function ID is configurable from Theme Settings.
- Product-level promotional controls are set through product metafields, with JSON used where a rule needs it.
- A dedicated JSON testing page helps generate and test the discount metafield data.
- Simple price adjustments can be made manually, without JSON.
- Scripted discounts can be removed programmatically for selected products.
For the combination problem, the team removed the discount-combination condition on the relevant US and EU landing-page and offer experiences, so offer discounts no longer combine with other product discounts on those pages.
Lucent delivers this kind of Function-based work through its Shopify Plus development services.
Checkout and Customer Experience
The "You May Also Like" section reads the customer's cart and leaves out any product already in it.
For Skinsider, the slider cart now hides Add Membership for logged-in customers with an active membership. Logged-out visitors and non-members still see it.
For Lip Trio, the team aligned the tagging with an existing implementation used for similar offers. Participating products now carry LipTrio-B2GF and LipTrio-40OFF at product level, and the order-level tags are kept. The change was reviewed and confirmed to work as expected.
For EU and UK customers, Lucent added a Your Marketing Preferences section. It opens with "We'd love to keep in touch about our latest offers, products and important Wonderskin updates." Customers choose Post, Email or SMS are told they can change their preferences at any time and can follow a link to the Privacy Policy.
