What is Shopify Functions?
Shopify Functions are small programs written by app developers that run inside Shopify's checkout to customize discounts, shipping and payments.
They run in checkout rather than in the shopper's browser. For discounts, Shopify's developer documentation describes Functions as a way to create discount logic that is not offered out of the box, executed by Shopify when shoppers add products to the cart.
Functions are the replacement for Shopify Scripts, the older Plus-only mechanism, so a discount built on a Function is applied by Shopify in checkout rather than simulated in the cart.
Read more
See also
Sources
- Shopify.dev: About discounts (Shopify Functions) (accessed October 11, 2026)