---
title: "New: Support for nested cart lines - Shopify developer changelog"
description: Shopify’s developer changelog documents all changes to Shopify’s platform. Find the latest news and learn about new platform opportunities.
source_url:
  html: https://shopify.dev/changelog/new-support-for-nested-cart-lines
  md: https://shopify.dev/changelog/new-support-for-nested-cart-lines.md
---

[Back to Developer changelog](https://shopify.dev/changelog)

August 6, 2025

Tags:

* Functions
* Checkout UI
* Customer Account API
* Customer Accounts
* Liquid
* Storefront GraphQL API
* Webhook
* 2025-10

# New: Support for nested cart lines

New fields have been introduced to enable parent-child (nested) relationships between cart lines, supporting use cases such as warranties, engravings, and gift-wrapping.

* Nested cart lines are now supported in the Cart AJAX API, and as of version 2025-10, in Storefront API and Checkout UI Extensions.

* Nested (child) lines reference their parent using a dedicated parent field: Use `parentId` or `parent_line_key` (Cart AJAX API), `parentID` (Checkout UI Extensions), `parent.lineId` or `parent.merchandiseId` (Storefront API).

To learn more about the impacted APIs and fields, click [here](https://shopify.dev/docs/apps/build/product-merchandising/nested-cart-lines).