---
title: cartLinesUpdate - Storefront API
description: Updates one or more merchandise lines on a cart.
api_version: 2026-01
api_name: storefront
type: mutation
api_type: graphql
source_url:
  html: 'https://shopify.dev/docs/api/storefront/latest/mutations/cartLinesUpdate'
  md: 'https://shopify.dev/docs/api/storefront/latest/mutations/cartLinesUpdate.md'
---

# cart​Lines​Update

mutation

Updates one or more merchandise lines on a cart.

## Arguments

* cart​Id

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

  required

  The ID of the cart.

* lines

  [\[Cart​Line​Update​Input!\]!](https://shopify.dev/docs/api/storefront/latest/input-objects/CartLineUpdateInput)

  required

  The merchandise lines to update.

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

***

## Cart​Lines​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

* ### cartLinesUpdate reference