Indicate one or more (separated by comma) webhook URLs to notify about the status of the message delivery.That is, If you want to receive the status of the message you've sent to your subscribers, you need to specify your endpoint.
Your endpoint must have a HTTP POST access method and receive a JSON body.
The URL is the external callback where the events of the Email will be registered and published. Once an email is processed, its status will be posted to your callback URL.
To view the full list and meaning of each status, please refer to the Email Status section.