---
title: cartDiscountCodesUpdate - Storefront API
description: >
  Updates the discount codes applied to a
  [`Cart`](/docs/api/storefront/2026-01/objects/Cart). This mutation replaces
  all existing discount codes with the provided list, so pass an empty array to
  remove all codes. Discount codes are case-insensitive.


  After updating, check each
  [`CartDiscountCode`](/docs/api/storefront/2026-01/objects/CartDiscountCode) in
  the cart's
  [`discountCodes`](/docs/api/storefront/2026-01/objects/Cart#field-Cart.fields.discountCodes)
  field to see whether the code is applicable to the cart's current contents.
api_version: 2026-01
api_name: storefront
type: mutation
api_type: graphql
source_url:
  html: >-
    https://shopify.dev/docs/api/storefront/latest/mutations/cartDiscountCodesUpdate
  md: >-
    https://shopify.dev/docs/api/storefront/latest/mutations/cartDiscountCodesUpdate.md
---

# cart​Discount​Codes​Update

mutation

Updates the discount codes applied to a [`Cart`](https://shopify.dev/docs/api/storefront/2026-01/objects/Cart). This mutation replaces all existing discount codes with the provided list, so pass an empty array to remove all codes. Discount codes are case-insensitive.

After updating, check each [`CartDiscountCode`](https://shopify.dev/docs/api/storefront/2026-01/objects/CartDiscountCode) in the cart's [`discountCodes`](https://shopify.dev/docs/api/storefront/2026-01/objects/Cart#field-Cart.fields.discountCodes) field to see whether the code is applicable to the cart's current contents.

## Arguments

* cart​Id

  [ID!](https://shopify.dev/docs/api/storefront/latest/scalars/ID)

  required

  The ID of the cart.

* discount​Codes

  [\[String!\]!](https://shopify.dev/docs/api/storefront/latest/scalars/String)

  required

  The case-insensitive discount codes that the customer added at checkout.

  The input must not contain more than `250` values.

***

## Cart​Discount​Codes​Update​Payload returns

* cart

  [Cart](https://shopify.dev/docs/api/storefront/latest/objects/Cart)

  The updated cart.

* user​Errors

  [\[Cart​User​Error!\]!](https://shopify.dev/docs/api/storefront/latest/objects/CartUserError)

  non-null

  The list of errors that occurred from executing the mutation.

* warnings

  [\[Cart​Warning!\]!](https://shopify.dev/docs/api/storefront/latest/objects/CartWarning)

  non-null

  A list of warnings that occurred during the mutation.

***

## Examples

* ### cartDiscountCodesUpdate reference