Checkout customization, Shopify Functions vs Magento module system?
This is the deepest architectural difference. It bites brands with non-standard checkout flows.
Shopify Plus checkout = Shopify Functions:
- Three function types: cart-and-checkout-validation, discount, delivery / payment customization
- Written in Rust or JavaScript, sandboxed, deployed via Shopify CLI
- Sub-50ms execution budget, runs on Shopify infra
- Powerful for: tiered discounts, conditional shipping rates, fraud blocks, B2B PO entry, custom payment routing
- Bounded: can’t add a custom field beyond what Checkout Editor exposes, can’t add a step, can’t reorder steps, can’t change checkout layout beyond Editor blocks, can’t hold-and-resume across sessions, can’t do server-side data lookups longer than 5ms
Adobe Commerce checkout = full Magento module:
- Override Knockout or Hyvä checkout entirely
- Add steps, add custom fields with validators, route based on cart contents
- Integrate ERP-driven shipping rates (live SAP query)
- Surface customer-credit balance live, hold-and-resume checkout across days
- Multi-warehouse split shipping with per-warehouse stock allocation
- Sample-cart workflows (free sample + paid item in same cart with separate fulfillment)
- No execution time limit, anything PHP can do
The Plus ceiling is real. Brands with subscription + one-time-buy mixed, B2B PO entry, multi-warehouse split-shipping, or sample-cart workflows hit it within 6 months. If checkout is your competitive advantage (or part of your B2B procurement integration), Adobe Commerce. If checkout fits the Shopify-Editor-plus-Functions model, Plus is faster to ship.