Shopify Functions

Shopify's mechanism for extending checkout behavior — discounts, shipping, and payment methods — with serverless functions written in Rust or JavaScript.

Positioned as the successor to Shopify Scripts (Plus-only, Ruby), Functions are available on all plans. Crucially, checkout logic can now be packaged and distributed as an app.

We implement Functions for employee discounts, tier-based member discounts, and custom shipping logic, evaluating adoption together with Checkout Extensibility migrations.