What is the Webhook URL setting for?
Certain requests, such as looking up an email address, may have an asynchronous response (since there’s some complex background processing involved). For these requests you can either poll the endpoint, or give us a webhook URL you want to be called when the request has finished processing.
You can set a webhook URL endpoint in your account API Settings to be used with all requests.
For more information, see the docs.
Please be cautious when using this field. Data will be sent to this URL on every request, so this field should only be filled if you have a properly configured webhook to handle the data.