GraphQL Storefront API returns incorrect domain when creating checkout

[jahilldev]

Hi there,

We're using the Storefront API to create a checkout URL for customers in a custom order journey. The API response includes the `webUrl` to redirect a customer to for checkout. However, this includes in the default domain, not the vanity version (e.g `xx.myshopify.com` instead of `xx.com`).

https://shopify.dev/docs/api/storefront/2023-10/mutations/checkoutcreate

I don't see anyway to configure this in the API request input, and doing string replacement on the checkout URL doesn't seem to work either, as the customer is redirected back to the home page.

Can anyone point me in the right direction? This is key for GA and analytics tracking for us.

Many thanks

James