2025-10-30: Cart Service - external discounts on cart level

Overview

Cart Service now supports applying external discounts directly at the cart level. This enables external systems (such as ERP systems) to apply cart-wide discounts that are calculated outside of Commerce Engine.

New attribute added to cart:

• externalDiscounts - an array of external discounts that can be applied to the entire cart, similar to how external discounts can be applied at the item level

Each external discount includes:

• id - unique identifier of the external discount
• discountType - type of discount: PERCENT, ABSOLUTE, or FREE_SHIPPING
• value - the discount value (percentage for PERCENT type, or monetary amount for ABSOLUTE type)
• discountCalculationType - determines how the discount is applied:

  • TOTAL - discount is spread across products, product fees, and shipping cost
  • SUBTOTAL - discount is spread across products only, without fees or shipping
• sequence - defines the order in which multiple discounts are applied

Applying external discounts to a cart requires the cart.cart_manage_external_prices scope.

Updated endpoints

Endpoint	Description
Updating a cart	The externalDiscounts attribute has been added.
Retrieving cart details by ID	The externalDiscounts attribute is included in the response.

Known problems

There are no known problems.