# What is a DLR (Delivery Receipt)?

> A DLR is the asynchronous confirmation that an SMS has been delivered (or failed to deliver) at the handset. It is generated by the recipient operator's SMSC, returned over SMPP via deliver_sm or HTTP webhook, and carries a state (DELIVRD, UNDELIV, REJECTD, EXPIRED) plus an operator-specific error code.

- Canonical URL: https://www.broadnet.me/answers/what-is-dlr
- Language: en
- Last reviewed: 2026-05-27
- Publisher: BroadNet (https://www.broadnet.me)

## What 'delivered' actually means

DELIVRD means the recipient's MSC has reported successful radio delivery to the handset — the network is satisfied. It does not mean the user read the message, opened the messaging app, or even had their screen on. Treat DLR as a network-level acknowledgement, not a read receipt. (For read receipts, use RCS or WhatsApp.)

## The error codes you actually see

GSM Cause Codes 1–127 are the protocol-level reasons (absent subscriber, equipment failure, etc.). SMPP error codes 0x0000–0x00FF are the SMPP-level reasons (invalid source address, congestion). Operator-specific TLVs sometimes carry richer context (radio out of coverage, handset memory full). A good aggregator translates the noisy operator codes into a clean error taxonomy you can act on. BroadNet's DLR feed normalises across 200+ operators into a 25-code error vocabulary.

## Why DLRs come back late

Many reasons. Roaming subscriber off-network for hours. SMSC store-and-forward retrying for the validity period (default 24 hours; up to 72 hours for some carriers). Operator A2P routing path going through three intermediate SMSCs each adding their own queue delay. Mature monitoring tracks DLR latency p50/p95/p99 by destination operator and alerts when a route degrades — see /products/dlr-monitoring patterns.

## What to do with the DLR

Three actions. Mark the message as delivered/failed in your system of record. Trigger downstream business logic (cart recovery flow continues, OTP retry kicks in). Feed it back into a route-quality scoreboard so your aggregator can rebalance. The third is what separates a CPaaS from a wire — BroadNet uses your DLRs to drive route selection in real time.

## Related

- [All answers](https://www.broadnet.me/answers)
- [Glossary](https://www.broadnet.me/answers)
- [Why are my SMS messages not being delivered?](https://www.broadnet.me/answers/why-are-my-sms-not-delivering)
- [MO vs MT — what's the difference?](https://www.broadnet.me/answers/what-is-mo-vs-mt)
- [What is the SMS validity period?](https://www.broadnet.me/answers/what-is-validity-period)
- [HMAC-SHA256 for DLR webhook signing — how and why](https://www.broadnet.me/answers/hmac-sha256-dlr-signing)
- [What is an ESME?](https://www.broadnet.me/answers/what-is-esme)
- [Webhook setup](https://www.broadnet.me/developers/webhooks)
- [SMPP error-code lookup](https://www.broadnet.me/tools/smpp-error-codes)
- [SMS API](https://www.broadnet.me/products/sms-api)