Question

What are the different Delivery Receipts (DLRs) the Vonage API platform might return?

Applies To

• Outbound SMS
• Deliver Receipts

Answer

The default expiry time for a SMS within the Vonage API platform is 72 hours. Within this 72 hours there might be 2 types of DLRs received from the supplier:

• Intermediate DLR: The carrier (supplier) passes an intermediate status confirming that the message has been received on their side and it is being processed. The status of an intermediate DLR can be:
  • Accepted: The target carrier has accepted to send this SMS. Most often received.
  • Buffered: This message is in the process of being delivered.
• Final DLR: Indicates the final status of the message. The different statuses that may be received from the carrier on a final DLR are the following:
  • Delivered: This message has been delivered to the phone number.
  • Expired: The message expired on the carrier or network side.
  • Failed: The target carrier failed to deliver this message.
  • Rejected: The target carrier rejected this message.

If the SMS has not received a final DLR after 72 hours of having been sent, the Vonage API platform will generate a final DLR with an expired status and will be passed to the client in the form of a callback to the client's webhook.

Any DLR received from the carrier after the internally generated final DLR with an expired status will be ignored, and not matched against the original Message ID. In this case, we will be able to see a DLR matching the GW_ID with the original MT in the connector logs, but it will not be matched against the account ID or internal Message ID of the original MT.