Main issue: Attempts to implement checkout validations (e.g., verifying a customer VAT number before checkout) hit a GraphQL error: “Access denied for checkoutServerExtensionCreate. Required access: The shop must have access to checkout server extensions.”
Key points:
The error occurs when following Shopify’s cart/checkout validation tutorial and running the checkoutServerExtensionCreate mutation.
Adjusting Admin API or Storefront API access scopes in the app configuration does not fix it; the message is not about standard access scopes.
Root cause: Checkout Server Extensions are gated behind a Developer Preview. Regular dev stores lack this feature.
Resolution/Actions:
Create a new development store with the relevant Developer Preview enabled (via Shopify’s Developer Previews page).
In that store’s UI, enable the Checkout/Server Extension preview feature. After this, the mutation works.
Context:
Goal is to block/validate checkout based on the presence of a VAT number captured at account creation (stored in customer notes). Checkout validations are feasible via Checkout UI/Server Extensions once the preview is enabled.
Status: Resolved with the developer preview setup. Images in the thread show app scope settings (not sufficient) and the preview toggle (required).
I am trying to build the custom app. The idea is to validate the customer VAT number. I have build the field that registers customer VAT number when creating account. I can see it store VAT in customer notes.
Now I want to validate this VAT is present or not before making checkout. Is this something possible using Checkout UI extension?
Hello @sushilsth21 , @HagenH
Here are the Steps you can follow
If you are using custom app i.e product-listing as show in screenshot below , So you can give permission to that particular app to fetch/upload data.
Steps to give Permission to your app :
Apps->Apps and sales channels->develop apps
select your app name then go configuration
where you can find list of permission for your particular app
1.Admin API access scopes
2.Storefront API integration
thank you so much for your reply. Unfortunately this does not solve the error. The configuration just allows to change the normal acces scope for an app, created by the shop owner. But even then those are normal access scopes. The error message does not hint to the lack of a normal access scope. It says
The shop must have access to checkout server extensions.
and none of the APIs be it Admin or Storefront has this particular access.
I found out how to make it work. You actually have to create a new dev store with that special kind of preview enabled. A normal dev store won’t do. See here.
In the UI you can then enable the respective extension preview: