---
title: >-
  Cart and Checkout Validation Functions now run in online store cart - 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/cart-and-checkout-validation-functions-now-run-in-online-store-cart
  md: >-
    https://shopify.dev/changelog/cart-and-checkout-validation-functions-now-run-in-online-store-cart.md
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  createdAt: '2023-08-18T17:39:32-04:00'
  postedAt: '2023-08-21T23:00:00-04:00'
  updatedAt: '2024-02-02T10:05:16-05:00'
  effectiveAt: '2023-08-21T23:00:00-04:00'
---

August 22, 2023

Tags:

* API

# Cart and Checkout Validation Functions now run in online store cart

Cart and Checkout Validation Functions now run on the online store cart (they previously only ran on the storefront cart API). You can now apply custom validation logic to buyers on the online store as well as custom storefronts.

Learn more about Cart and Checkout Validation Functions on [Shopify.dev](https://shopify.dev/docs/api/functions/reference/cart-checkout-validation).