Shopify Glossary Terms

Shopify Functions (which replaced Shopify Scripts) let developers write custom backend logic that runs within Shopify's infrastructure. They're used for discount logic, payment method customisation, shipping rate calculation, and cart/checkout validation.

Unlike apps that run on external servers, Functions execute directly on Shopify's servers at the point of need - during checkout, cart calculation, or order processing. This means they're fast and don't add external dependencies to critical commerce paths.

Common use cases include tiered discounts based on cart value or customer tags, hiding payment methods based on product type, custom shipping rates based on order weight or destination, and automatic bundle pricing. Functions work alongside Checkout Extensibility - Functions handle the logic, UI Extensions handle the presentation.

For Shopify Plus merchants, Functions replace a lot of the custom middleware that used to sit between Shopify and checkout. Less infrastructure to maintain, fewer points of failure.

Think: custom commerce logic that runs inside Shopify, not around it.