The Easyship API returns labels asynchronously
Asynchronous responses mean that Easyship won't be returning labels you have requested immediately. After your Label API POST call, you will get a successful response from the Easyship API, but without the label. This allows your implementation to work on other tasks whilst Easyship is retrieving your data.
When you make a request, we then call the APIs of the courier to purchase and generate the label, as well as begin producing the tax and customs docs.
By using an asynchronous response, it won't block the rest of the application, and we will use your
callback_url to notify you when the documents are ready,