The simple key authentication is used for API implementations within your account. 

The Simple Key is the appropriate authorization option for the following API's:

• Order
• AutoOrder
• Item
• Fulfillment
• Customer
• Coupon
• User

Steps

Log into your UltraCart account and then navigate:

From the Authorized Applications page, select the "Authorized Applications" tab:

Then in the configuration section that appears, enter an App, then select Simple Key from the drop down list for "Authentication Key", and, optionally, enter in the Allowed IP Addresses. Then in the permission section to the right, select only the specific Read/Write permissions for the API:

Click Save to save your Simple Key:

Related Documentation

https://www.ultracart.com/api/#topics.html