--- title: Cart and Checkout Validation Function are now available for custom apps - 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-function-are-now-available-for-custom-apps md: https://shopify.dev/changelog/cart-and-checkout-validation-function-are-now-available-for-custom-apps.md --- [Back to Developer changelog](https://shopify.dev/changelog) July 26, 2023 Tags: * API # Cart and Checkout Validation Function are now available for custom apps The Shopify Functions API for cart and checkout validations is now available on production stores for custom apps. Learn more about building cart and checkout validations in our dev docs: [Cart and Checkout validations](https://shopify.dev/api/functions/reference/cart-checkout-validation)