Sorry, my english is poor.
My app get the webhook when create checkout, my db always show primary key is not unique errors.
And I make a new checkout, the new id is less than checkout id in another shop.
So I eagerly want to know checkout ID is unique to the store or the Shopify?
!!! Checkouts List
The ID is not scoped to the Shop but is unique number on the platform as a whole.
If you are getting errors perhaps you have getting multiple webhooks for the same checkout. You'll need to account for that.