For an SMS sent via Exotel SMS API, you can find out the delivery Status of the SMS via two means:
A. PULL: You can pull the status by querying Exotel for the specific SMS that you sent.
For this you need to make a GET request to
https://<ExotelSid>:<ExotelToken>@api.exotel.com/v1/Accounts/<ExotelSid>/SMS/Messages/<SmsSid>
where
ExotelSid is your Exotel Sid
ExotelToken is the token <--- You can get this from the Settings page
SmsSid is the "Sid" (unique id) of the SMS that you got in response to your send request
B. PUSH: You can have Exotel push the SMS status to you after the SMS reaches any terminal state (ie, "sent", "failed" or "failed-dnd").
For this, you need to pass an additional parameter "StatusCallback" along with your other parameters (like 'From', 'To' and 'Body').
=> This parameter should be a URL that is hosted by you. Ex: http://example.com/
=> Exotel will make a POST request to the above URL with the following parameters:
- SmsSid : The 'Sid' of the SMS
- Status : The Status of the SMS. For a detailed description of these Statues, See Exotel SMS status codes
- DateUpdated : The time when the SMS was last updated