Cart Warnings in Storefront API Cart

As of API version 2024-10, inventory errors about stock levels will no longer be included in the userErrors of cart mutations. Inventory errors will now be available in a new return field, warnings and will contain explicit code values of MERCHANDISE_NOT_ENOUGH_STOCK or MERCHANDISE_OUT_OF_STOCK.

Warnings will be available on all cart mutations to show automatic changes that occurred during the mutation. You can use warnings to manage items in your cart or display information to a buyer. For example, out of stock lines can be easily removed from a cart by using the target field included in the warning as the input to a call to CartLineRemove.

Learn more about cart warnings on Shopify.dev.