About the Product Discount Function API

The Product Discount API enables you to create a new type of discount that is applied to particular product variants or cart lines.

Example use cases

Money off a product. For example, 20% off shirts.
Money off a product variant. For example, $5 off blue shirts.
Money off a cart line. For example, 10% off products with a name engraving option.
Buy a specific quantity of a product for a specific amount. For example, $5 off up to 2 blue shirts.
Buy a specific amount of a product, get a second amount at a discount. For example, buy 4 shirts and get 2 blue shirts free.

A command-line tool for building Shopify apps.

Consult the GraphQL reference for the Product Discount API.

If you want to migrate an existing line item script to Shopify Functions, then you can use the following mappings:

Shopify Scripts method	Description	Shopify Functions object	Additional context
`change_line_price`	Applies a discount to a cart line for a product by specifying a new reduced price, and a message	Product discount	Apply one or more Discounts by specifying the Value (`percentage` or `fixedAmount` off), Target(s) (either a `cartLine`, or `productVariant`), and an optional message.
`split`	Splits a product into multiple lines so that you can apply discounts to partial quantities	Product discount	Use the optional `quantity` field in Target (either a `cartLine`, or `productVariant`) to optionally limit the number of units the discount may be applied to.
`change_properties`	Adds or changes a line item property	Not available	Refer to applyAttributeChange in the checkout UI extensions API to apply attribute changes.
`reject`	Disallows a discounts code from being applied at checkout	Not available	Use a Product discount or Order discount function that contains the necessary logic. For example, you can use conditions to exclude a discount from applying.

Input cart.deliveryGroups is always an empty array for this function.
Active automatic app discounts using Shopify Functions are applicable for all Shopify sales channels that use Shopify Checkout, including the Online Store and Shopify Point Of Sale (POS).