Shopify Functions

Overview

Shopify Functions execute custom business logic in a WebAssembly sandbox at checkout: discounts, payment filtering, delivery customization, and cart transforms. They run server-side with strict constraints (11ms execution, 1MB memory, no network access) and replace Shopify Scripts.

Prerequisites

• Shopify CLI 3.x+ installed (npm install -g @shopify/cli)
• Shopify Partners account with a development store
• App configured for the target function API type

Instructions

Step 1: Configure the Function Extension

# extensions/product-discount/shopify.extension.toml
api_version = "2025-01"
type = "product_discounts"