---
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

* cartId
* lines

***

## Cart​Lines​Update​Payload returns

* cart
* userErrors
* warnings

***

## Examples

* ### cartLinesUpdate reference