Cart and Checkout Validations are now available in Developer Preview
API
Effective February 09, 2023
The Shopify Functions API for cart and checkout validations is now available in the Checkout Extensibility developer preview.
This API allows you to apply validation rules that run in both the cart and checkout, ensuring that purchases meet certain criteria before checking out, or completing the order.
Learn more about building cart and checkout validations in our dev docs: Cart and Checkout validations