API Documentation and Discovery
To start, Spreetail will provide this developer portal for the most up-to-date OpenAPI spec of our APIs. You can use that file to import the API collection into Postman or Insomnia in order to test the APIs.
Sandbox Environment
The sandbox environment is designed for testing authentication and interaction with our endpoints, even if you don't have data in our systems. It also serves to prevent the creation of any orders that shouldn't be fulfilled during testing.
NOTE: The Auth endpoints are linked to a live Auth service, allowing you to authenticate and generate new Credentials directly from this site.
Sandbox APIs: 
Swagger UI
Creating Sandbox Orders - Special Behavior
When creating a new Order, to test creation of an object, give the CustomerOrderId a prefix of "CREATE-". If you would like to test the response as if the order ID already exists, simply omit that prefix and the endpoint will act as if another order already exists with that ID.
Sandbox orders with a CustomerOrderId that begins with a "CREATE-" prefix will return a 200 code with a new order object. Any other CustomorderId will result in a 400 code, with error message Order with this CustomerOrderId already exists.
Production Environment
This is our live environment, which you can use to see all of the actual inventory within our systems, or create orders that will be fulfilled.
Spreetail APIs: 
Swagger UI