DLT Guidelines

Distributed Ledger Technology (DLT)

The Distributed Ledger Technology (DLT) is a blockchain based technology used by the Telecom Regulatory Authority of India (TRAI) to check for unsolicited SMSs sent to the end users. It was activated as the Telecom Commercial Communications Customer Preference (TCCCP) Regulations in April, 2021. Post these regulations, principal entities (PEs) can only send SMSs which are registered on the Distributed Ledger Technology (DLT) platform.

Categories of Message Templates

A. Transactional

Any message which contains One time Password (OTP) and requires to complete a banking transaction initiated by the bank customer will only fall under this category. This is applicable to all banks (national/Scheduled/Private/Government and even MNC banks)

Example :

  • OTP message required for completing a Net-banking transaction.
  • OTP message required for completing credit/debit card transaction at a Merchant location.

B. Service Implicit

Any message triggered in response to a user action or arising from his relationship with the sender, that is not promotional, will fall in this category. These messages will not be blocked for subscribers who have otherwise blocked service messages also. Informative SMS and other OTPs fall into this category.

Example :

  • Confirmation messages payment transactions, purchase confirmation, delivery status etc.
  • OTP messages for payments through Payment Wallet over E-Commerce website, OTP messages for App login
  • Periodic balance info, bill generation, bill dispatch, due date reminders, recharge confirmation (DTH, cable, prepaid electricity recharge, etc)
  • Messages from schools-attendance/transport alerts.
  • Messages from hospitals/clinics/pharmacies/radiologists/pathologists about registration, appointment, discharge, reports.
  • Confirmatory messages from app-based services.
  • Govt/DOT/TRAI mandated messages.
  • Service updates from car workshops, repair shops, gadgets service centres.
  • Directory services like Justdial, yellow pages.
  • Day-end/month-end settlement alerts to securities/Demat account holders.

C. Service Explicit

These are the messages which requires explicit consent from customer, that has been verified directly from the recipient in robust and verifiable manner and recorded by consent registrar. Any service message which doesn’t fall under service-implicit category. There may not be any need for explicit consent to all other subscribers, who have not blocked service messages

Example :

  • Messages to the existing customers recommending or promoting other products or services.
  • Re-engagement messages sent to existing customer like "It's been 30 days since you last visited our platform. Visit now and explore our new products"

D. Promotional

Any message sent with an intention to promote or sell a product, goods or service will fall in this category. Service content mixed with promotional content will also be treated as promotional. Explicit consent is not needed to send such messages.

Example :

  • Offer messages to new users like "Shop for 3999 and get 10% off on our App. Limited time offer. T&C. Download the App now..."
  • Pack Upgrade message to existing customers like "Upgrade to our pro plan. Get credit limit of 1k and pay once in 30 days. Click here...."

General Template Validation

  • Organization name or brand name must appear in the template.
  • Transaction Content Template is only available for banks, digital wallets duly permitted/approved by RBI.
  • Transaction/Service explicit/Service implicit templates can be created under Alpha-headers.
  • Promotional templates can be created under Numeric headers.
  • 2 or more spaces are not supposed to be used between 2 words, before word or after word.
  • Trans/Service category messages should have variable mandatorily.
  • Promo category can have complete fixed content or with variable part.
  • Maximum allowed variable length is 30 characters. Spaces, special and regular characters, all qualify as characters.
  • All special characters are being allowed currently.
  • Adding non-english alpha numeric and special characters in message qualify as UNICODE SMS which has a lower character limit per message than TEXT SMS
No of messagesText charactersUnicode characters
1 SMS16070
2 SMS306134
3 SMS459201
4 SMS612268
5 SMS765335


Using another entity name in templates

If Principal entity(PE) uses the name of another entity in their templates, the Telecom service provider (TSP) will register the same on the presumption that there exists a business relationship with that entity without having any accountability to validate the same. Valid proofs and justification if sought pursuant to any complaints by TRAI/PE shall have to be furnished by the registering PE.

Do's for Template content

  • Use promotional category for communications intended to send from numerical sender id only.
  • Service – explicit category needs to link consent template as well, without which the template gets rejected.
  • Values like amount, date, a/c no, merchant names, OTP, codes, URL, customer names, card type, etc. should be replaced with variables.

Don'ts for Template content

  • Not linking consent templates for content template categories “promotional” & “service – explicit”.
  • Same content template should not be tagged against multiple headers.
  • Selecting “Transactional” category by non-banking enterprises.
  • Using double spaces in templates (this can be pre-checked by verifying the template on any text editor before template submission).
  • The whole template should not be variable {#var#}, the customer is required to mention the template content in between the variables. Templates should not be less than 6 char long