Delivery Receipt (DLR) FAQsFollow
What is a Delivery Receipt?
A Delivery Receipt (DLR) is an acknowledgement from a destination carrier network that a message was successfully accepted or rejected (and the reason the message was rejected). Bandwidth supports DLRs on SMS and MMS if a customer has their requested delivery status flag set appropriately.
There are two types of DLRs: intermediate and final (handset).
What is an intermediate DLR?
An intermediate DLR means the end carrier has received the message and it's usually considered successful. In the US and Canada market for local long codes, ACCEPTD (SMPP 3.4 ACCEPTD) will be the most precise indicator of a successful message. Specifically on Local A2P & Local P2P messaging, you will only see Carrier DLRs supported.
Note: Some destination carriers, even after sending back an acknowledgement, may not be able to deliver the message due to downstream spam filters or other reasons. This is on a per carrier basis. If Bandwidth does receive a clear rejection for a message, you'll always see a failed message delivery status reflected in your response or callback.
Even though intermediate DLRs don't represent actual final delivery to a handset, knowing that your message was received at a point along the delivery path to your customer’s handset can help with troubleshooting if you receive complaints of customers not receiving messages.
What is a final or handset DLR?
A final or handset DLR is a confirmation that your message was delivered to the recipient’s handset and will be sent back to us as DELIVRD (SMPP 3.4).
Note: Depending on the carrier, handset DLRs are only possible for A2P traffic on toll-free numbers and short codes. Carriers only provide intermediate or carrier DLRs for all P2P and A2P long code routes in the U.S. and Canada. The downstream carrier is ultimately responsible for returning a DLR in response to a request for one. If a carrier does send a final DLR, we'll send that back to you.
How do I receive a DLR?
DLRs are always requested for V2 Messaging API users, while SMPP and MM4 customers must have their requested delivery status flag set appropriately. For more information on how to set up callbacks for HTTP, please see our developer docs.
When will I receive a DLR?
Delivery receipts aren't guaranteed even when they're requested from destination operators. When Bandwidth receives them, delivery receipts are typically processed in 2 hours or less. If a DLR isn't received within 2 hours, you'll receive a DLR timeout error (expired DLR).
I received an expired DLR. Does this mean my message wasn’t delivered?
Not necessarily! An expired DLR or timeout DLR means Bandwidth didn't receive a DLR from the destination carrier or handset within the timeout window (the period we are "listening" for DLRs). An expired DLR (902 or 9902 error code) means Bandwidth doesn't know the delivery state of the message, given no delivery receipt from the carrier.
It's generally accepted in the industry that carriers have up to 72 hours to return a delivery receipt. We tested expanding the timeout window but didn't see a dramatic decrease in expired DLRs. Given the possible options for why a DLR wasn't received (it arrived after the timeout window, the carrier doesn't not support DLRs, or a DLR was never sent), we see indications that expired DLRs happen most often when no DLR has been sent. However, our testing does show that in most cases the message is received by the handset.
DLR availability by product
This table indicates what type of DLRs are available by product when supported by the carriers.
|Messaging reach||Carrier DLR||Handset DLR||Description|
|US Short Codes (SMS)||Yes||Yes||Where supported by the carriers, a final/handset DLRs will be sent in most cases.|
Zone 1 SMS and MMS (US and Canada)(US Long Codes or Text-Enabled Landlines)
|Yes||No||Only intermediate DLRs are available. However, these DLRs still indicate that your message has been passed to the carrier network for delivery.|
Zone 1-5 SMS(International short code or long code text-enabled numbers)
|See note||See note||On a case-by-case, country-by-country basis, there may or may not be DLRs available.|
Toll-free SMS and MMS(US Text-Enabled Toll-Free Numbers)
|Yes||Yes||When supported by the carriers, a final/handset DLRs will be sent in most cases. For more information about which carriers support DLRs for toll-free, please visit our messaging reach list.|
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