Checkbook Fields setting

Field	Description
Web service Url	Sandbox: https://sandbox.checkbook.io/v3/ Produciton: https://www.checkbook.io/v3/
Api Key	From developer tab copy API Key. See below
Secret Key	From developer tab copy Secret Key. See below

Important Note To retrieve the keys from Checkbook, navigate to checkbook.io account. Navigate to Settings > Developer.

Note: Keys for Sandbox and Production environment are different and needs to be appropriately applied.