DLR — Delivery Receipt
What is DLR?
A DLR (delivery receipt) is the status callback a carrier or messaging gateway sends back after an SMS, MMS, or WhatsApp message is submitted, confirming whether it was delivered, failed, or is still pending — and why, via a carrier status code. DLRs let a sending platform close the loop on every message instead of guessing from silence, and are the signal integrations use to retry a failed send or report an accurate delivery rate.
More detail
A DLR typically arrives asynchronously, seconds to minutes after the original send, since it depends on the destination carrier's own delivery confirmation. Platforms expose DLRs to integrators as a status field on the message record and, commonly, as an inbound webhook.
Delivery status alone does not confirm a human read the message — it confirms the carrier accepted (or rejected) it for delivery to the handset.
Frequently asked
- What does a DLR status of “undelivered” mean?
- It means the destination carrier rejected or could not deliver the message — common causes include an invalid or disconnected number, a blocked sender ID, or a carrier filter — and the accompanying status code identifies the specific reason.
- How fast do DLRs arrive after sending?
- It varies by destination carrier, from near-instant to several minutes, since the receipt depends on the terminating network's own delivery confirmation rather than the sending platform.
See also
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