We are experiencing issues with the Storefront GraphQL API related to the cartDiscountCodesUpdate mutation. Our app, that was working prior to the announcement of the change, currently using version 2025-01, attempts to apply discount codes with the following mutation and variables:
Mutation:
mutation cartDiscountCodesUpdate($cartId:ID!,$discountCodes:[String!]!) { cartDiscountCodesUpdate(cartId:$cartId,discountCodes:$discountCodes) { cart { id discountCodes { code applicable } discountAllocations { discountedAmount { amount currencyCode } discountApplication { ... } } lines(first: 10) { nodes { id quantity discountAllocations { discountedAmount { amount currencyCode } } merchandise { ... on ProductVariant { id title priceV2 { amount currencyCode } } } } } } userErrors { field message } }}
Variables:
{ "cartId": "gid://shopify/Cart/hWN4fe17z7JjAP19pBiUjWsw?key=15b560086f5a22def42eda11dd73b2d4", "discountCodes": ["DISCOUNT"]}
Response:
{ "errors": [ { "message": "Field 'cartDiscountCodesUpdate' doesn't accept argument 'discountCodes'", ... }, { "message": "Field 'discountApplication' doesn't exist on type 'CartDiscountAllocation'", ... }, { "message": "Variable $discountCodes is declared by cartDiscountCodesUpdate but not used", ... } ]}
We found the recent changelog for API version 2026-01 which states that discountCodes is now required for the mutation. However, these fields appear to not be accepted (or present) in version 2025-01. The documentation for 2025-01 still describes discountCodes as a valid field, but using it results in the errors above.
Please let me know if further data or logs are needed.
Thank you!