Shipping Discount Not Appearing

Shipping discounts have a few specific requirements that differ from standard item discounts. Work through these checks.

Is the promotion type set to Whole Cart (Final)?

Shipping discounts must use the Whole Cart (Final) promotion type. This type is always evaluated last, after all Item Group and Whole Cart promotions have run, which is what makes it the right tool for shipping and gift-with-purchase effects.

If the promotion is configured as an Item Group or standard Whole Cart type, it cannot discount shipping. Change the promotion type to Whole Cart (Final) in the Deducto Dashboard.

Is shipping method data included in the API request?

Deducto can only evaluate a shipping discount against shipping methods it knows about. If the shipping.methods array is absent from your Verify request body, no shipping discount will be calculated — even if the promotion is correctly configured.

Confirm that your storefront is including the shipping field in the request with all applicable shipping methods and their original prices. The discount result per shipping method appears in resolvedCart.shipping.methods[*].bestDiscount in the Verify response. If bestDiscount is null for all methods, Deducto either received no shipping data or no shipping promotion matched.

See the Custom Storefront guide and the Verify endpoint reference for how to structure the shipping data in the request.

Is your Shopify store on Plus?

Deducto applies shipping discounts through Shopify Checkout UI Extensions, which Shopify makes available only to Plus merchants. If your store is not on Shopify Plus, Deducto cannot apply shipping discounts through the checkout.

This is a platform limitation, not a Deducto limitation. See the Shopify Integration guide for details and workaround options for non-Plus Shopify stores.

Custom storefront integrations are not affected by this restriction — shipping discounts work on any custom storefront regardless of the underlying platform.

Is the trigger condition met?

Check whether the promotion has a trigger condition (such as a minimum cart subtotal) that the current cart doesn't satisfy. A shipping promotion with an unmet trigger will be silently skipped — it won't appear in rejectedPromotions. Verify the cart state against the promotion's configured conditions in the Dashboard.

Key point about multiple shipping promotions

If more than one shipping promotion could apply to the same shipping method, only the best discount is used — shipping discounts do not stack. The winning discount appears as bestDiscount on the shipping method in the Verify response.