Automatic discount price display — show sale prices before the cart

01 · Business Context

Travel-gear brand — Shopify · Consumer accessories. Scope and context as agreed with the client.

02 · Challenge

Shopify automatic discounts only apply in cart and checkout — product cards and PDPs show the full price, so shoppers never see the sale. The fix had to show discounted prices and strikethrough originals on cards, PDP and Quick Add, at variant level, in real time, without extra collection-page API calls.

03 · Architecture

An App whitelist picks which automatic discounts participate in display. A sync pipeline reads active discounts, expands them to variant level, writes a versioned snapshot to variant Metafields, then flips active_version for the theme to read. Shopify’s native automatic discount still handles the real cart and checkout price — Metafields are display-only, so no double discounting.

04 · Implementation

• Built the App whitelist with discount support validation and variant impact estimation
• Designed the sync pipeline: read, filter, expand to variants, snapshot, diff, batched Metafield writes, version flip
• Made webhooks trigger-only with a shop-level sync lock, retry and exception alerts
• Shipped theme display: product card / collection / PDP / Quick Add with discounted price, strikethrough original and X% OFF, updating live on variant switch
• Kept collection pages request-free via versioned Metafield reads

05 · Key Decisions

An App whitelist picks which automatic discounts participate in display — the architecture choice was driven by the business constraint, not by a preferred framework.

06 · Result

07 · Stack