Requirements to use the Carrier Service API
The Carrier Service API can be enabled based on your Shopify plan:
Advanced or Plus Plan: This feature is available by default and can be enabled directly.
Shopify Plan: You can request access to the API by reaching out to Shopify Support.
As of January 1, 2023 stores on Starter and Basic plans, will no longer be able to request access to the Carrier Service API. (Source)
Steps to enable the Carrier Service API
Please contact Shopify Support. They will assist you with the setup necessary for your store.
Visit Shopify Help Center.
Open up chat widget and type in
Hello, how can I enable carrier service api for my store
Click button "Chat with a Support Advisor"