DLT registration: definition and how it works
Published and updated
DLT registration is the Indian requirement that any business sending commercial or transactional SMS register itself, its sender headers and its message templates on a distributed ledger run by the telecom operators, under TRAI rules.
How it works
The Telecom Regulatory Authority of India issued the Telecom Commercial Communications Customer Preference Regulations in 2018. They require that commercial communication travel only under a header registered with the access provider. The operators implemented this as a shared ledger, so every registered sender, header and template is visible to every network.
A sender registers as a principal entity, proving its identity to one operator's DLT platform. It then registers headers, which are the six-character alphanumeric sender IDs recipients see, and content templates for each kind of message with placeholders for variables. TRAI's advice to senders is explicit that bulk senders of one time passcodes, transactional and service messages must register too, not only marketers. A message whose header or template does not match the ledger is dropped by the operator.
The system also carries customer preferences: the categories of promotional traffic a subscriber has opted out of. Operators scrub promotional messages against those preferences before delivery.
For a developer the practical effect is that alphanumeric sender IDs in India are never self-serve. They come after registration, and every message body must fit an approved template. Traffic sent from an ordinary SIM is outside the DLT system: it shows the number, and TRAI caps an ordinary SIM at one hundred SMS a day.
- TRAI regulations of 2018: commercial communication may only travel under a header registered with the access provider, and an unregistered subscriber who sends it can be capped and then disconnected. trai.gov.in, checked on September 4, 2026
- TRAI advice to senders: bulk senders, including senders of OTPs and transactional and service messages, must register as a principal entity, take a header and register content templates. trai.gov.in, checked on September 4, 2026
- A TRAI direction of 27 September 2011 limits an ordinary SIM to one hundred SMS per day. trai.gov.in, checked on September 4, 2026
How this applies with textbee
With textbee and an Indian SIM the sender is the phone number, not a registered header, so DLT templates do not apply, but the daily cap on an ordinary SIM does. That fits low-volume OTP and reply-based use where a real number is an advantage. High-volume transactional traffic in India belongs on a DLT-registered route.
Related terms
- DND registry: A DND (Do Not Disturb) registry is a national list of phone numbers whose owners have opted out of promotional calls and texts, which senders and operators must check before sending marketing.
- Alphanumeric sender ID: An alphanumeric sender ID replaces the sending phone number with a short text string such as a brand name, up to eleven characters, on routes and in countries that support it.
- Sender ID: The sender ID is what the recipient sees in the from field of a text message: a phone number, a short code, or a registered brand name.
- A2P and P2P messaging: P2P is a text one person sends to another; A2P is a text an application sends to a person, and carriers apply different rules, filters and prices to each.
Sources
- DLT registration, trai.gov.in, checked on September 4, 2026
- DLT registration, trai.gov.in, checked on September 4, 2026
- DLT registration, trai.gov.in, checked on September 4, 2026