The Nudge API uses API keys to authenticate all requests. Make sure to include your key in every request. This can be done by either appending the GET parameter
api_key or via the header as
Please keep your API key secret and secure! Do not share your API keys in publicly accessible areas such as GitHub, client-side code, etc.
You can find your API key in the Nudge Dashboard with your Tracking Script.
Click your profile in the top right of the dashboard, then select Show JS Snippet
Your API key will be displayed along side your Tracking Script as seen below.