Bundling logic inside Shopify's infrastructure.
This build replaces a third-party bundle app's discount logic with a native Cart Transform Function — no app overhead, no client-side JavaScript, no external server dependency.
Recorded on a Shopify Partners dev store with Plus-exclusive features enabled. Instruction count captured live from the Shopify Dev Dashboard — not estimated.
The Cart Transform Function
THE CART TRANSFORM FUNCTION:
This build replaces a third-party bundle app's discount logic with a Shopify Functions Cart Transform. The function runs inside Shopify's infrastructure at checkout — no client-side JavaScript, no outbound API calls, no external server dependency. Most bundle apps inject discount logic via app proxy or storefront JavaScript. That creates a failure surface outside Shopify's control. This architecture eliminates that surface entirely.
WHY RUST:
Rust compiles to a small WebAssembly module with no runtime layer to boot. On the September 9, 2026 run, this implementation completed the discount calculation in 181,184 instructions against Shopify's 11,000,000 budget, 1.6% of the ceiling.
THE FALLBACK DESIGN:
If the bundle expansion fails for any reason, the parent product passes through checkout at full retail price. No silent discount errors. No warehouse fulfillment mismatches. The failure mode is revenue-neutral.
Cart Transform [RUST] · 0 KB client-side JS · 0 outbound calls
FUNCTION: CART TRANSFORM [RUST]
- Runtime
- Shopify Functions (Plus-exclusive)
- Instruction Use
- 181,184 / 11,000,000
- Utilization
- 1.6% of ceiling
- Client-side JS
- 0 KB
- Outbound Calls
- 0
- Fallback
- Price parity on expansion failure
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