If you want to send OTPs, order updates, appointment reminders or promotional offers by SMS in India, you cannot simply buy credits and start sending. Since TRAI's Telecom Commercial Communications Customer Preference Regulations, 2018 (TCCCPR) came into force, every business sender, which the rules call a Principal Entity (PE), must register on a Distributed Ledger Technology (DLT) platform run by the telecom operators. Your sender IDs (headers), message templates and consent templates are all registered there too, and messages that do not match your registered details are blocked before they reach customers.
DLT registration is not difficult, but it has many small steps, and a mistake in any one of them leads to delayed approvals or failed messages. This guide explains the process in plain English and covers the rule changes TRAI introduced in 2024 and 2025.
What DLT is and why it exists
DLT is a shared, blockchain-style record kept by India's access providers (the mobile operators). It records who is sending commercial messages, which headers they use, what the approved message formats are, and which telemarketers carry the traffic. When an SMS is submitted, the operator checks it against these records: is the header registered to this sender, does the content match an approved template, and is the delivery chain declared?
The aim is to reduce unsolicited commercial communication (UCC) and fraud. For legitimate businesses, the benefit is that properly registered messages are more trusted and less likely to be confused with scams.
Who needs to register
You need DLT registration if your business sends commercial SMS to Indian mobile numbers, whether that is:
- Transactional messages, such as OTPs and banking alerts
- Service messages, such as order confirmations, delivery updates, appointment reminders or fee reminders
- Promotional messages, such as offers, sale announcements and new product launches
- Government messages, for government bodies (a separate category created in 2025)
This applies to businesses of all sizes, from a clinic in Bhopal sending appointment reminders to a national e-commerce brand. Your SMS provider (the telemarketer) is also registered on DLT, but it cannot register as you. The Principal Entity registration must be in your business's own name.
Step 1: Register your business as a Principal Entity
You register on one operator's DLT portal (Jio, Airtel, Vodafone Idea or BSNL each run one). Because the platforms share data, a registration on one is generally recognised across the others, so you do not need to register four times.
Typical requirements include:
- Legal business name exactly as on official documents
- PAN of the business, and GST registration if you have one (other identity documents may be accepted for some entity types)
- An authorisation letter on letterhead naming the person who will manage the account
- Business address and contact details, with a working email and mobile number for OTP verification
- Entity type, such as private limited company, partnership, proprietorship, trust or government body
Operators charge a registration fee that varies by platform and can change, so check the current fee on the portal you use. Approval usually takes a few working days once documents match. The most common reason for rejection is a mismatch between the name on the application and the name on the PAN or GST certificate.
After approval you receive a PE ID (entity ID). You will need it for every header, template and provider integration, so save it carefully.
Step 2: Register your headers (sender IDs)
The header is the sender name customers see, such as "DNDTMS". In practice, service and transactional headers have long been six-letter alphabetic IDs, while promotional traffic has historically used numeric headers. The 2025 amendment describes headers as drawn from an 11-character alphanumeric string, or as directed by TRAI, so the exact format accepted can change; your provider should confirm the current format when you apply.
Good practice for headers:
- Make the header clearly related to your brand name, because operators reject headers that look unrelated or that imitate another brand
- Keep proof that you have the right to use the name, such as a trademark, website or GST record
- Register separate headers for service and promotional use rather than mixing them
Since TRAI's February 2025 amendment to TCCCPR, headers carry a suffix so recipients can tell the type of message at a glance: -P for promotional, -S for service, -T for transactional and -G for government. You do not choose the suffix freely; it follows the category of the template and header. Our guide to SMS categories in India explains the categories in more depth.
Step 3: Register consent templates (where required)
If you plan to send "service explicit" messages, which are service messages that need the customer's explicit consent, you register a consent template describing what the customer agreed to. Customers can be asked to confirm consent through operator processes. Keep your own consent records too: the form, the date, the source and the exact wording.
Step 4: Register content templates
Every message you send must match an approved content template. A template has fixed text and variable placeholders, written as {#var#}, for the parts that change, such as a name, amount, date or OTP.
Example of a well-formed service template:
"Dear {#var#}, your appointment at City Dental is confirmed for {#var#} at {#var#}. Call 0755XXXXXXX to reschedule. -City Dental"
Rules and tips for templates:
- Choose the correct category. A promotional message registered as service or transactional is a violation. TRAI's August 2024 direction says templates registered under the wrong category will be blacklisted, and repeated offences can lead to suspension of the sender's services.
- Use variables sparingly. Templates made almost entirely of variables are usually rejected, because they could be used to send anything.
- Include your brand name so the customer knows who the message is from.
- Link one template to its intended header. The 2024 direction also says a single content template cannot be linked to multiple headers.
- Mention every URL, APK link or call-back number you intend to use (see the next step).
Each template receives a template ID, which your SMS platform sends with each message so the operator can match it.
Step 5: Whitelist URLs, APK links and call-back numbers
From 1 October 2024, operators stopped carrying messages that contain URLs, APK links or OTT links which have not been whitelisted by the sender, as confirmed in TRAI press release 80/2024. In practice this means:
- Register the exact domains you use in messages, such as your website, booking page or app store link
- Avoid generic link shorteners unless your provider offers a whitelisted, branded short domain
- Keep the domain consistent across templates, and update registrations before you change domains
If your messages suddenly stop delivering after a website change, a non-whitelisted link is one of the first things to check.
Step 6: Bind the PE-TM chain
TRAI also requires every message to be traceable from the sender to the recipient. You declare which telemarketers (your SMS provider and any intermediaries) carry your traffic, and this chain is "bound" on DLT. According to TRAI press release 92/2024, since 11 December 2024 traffic sent through an undeclared or mismatched chain is rejected.
When you switch or add an SMS provider, update the chain first. Many "messages failed overnight" problems come from a new provider being used before chain binding was completed.
Step 7: Connect your SMS platform and test
Give your provider your PE ID, header and template IDs. Send test messages to numbers on different operators and check delivery reports. Confirm that:
- The header appears correctly with its suffix
- Variables fill in as expected and do not exceed character limits
- Links open correctly and are whitelisted
- Promotional messages are not sent outside the permitted delivery window (generally 10 AM to 9 PM) or to customers who have opted out
Common reasons for rejection or blocked messages
| Problem | What usually causes it | How to fix it |
|---|---|---|
| Entity registration rejected | Name or document mismatch | Use the exact legal name on PAN/GST and a clear authorisation letter |
| Header rejected | Header not clearly linked to brand | Choose a header close to your brand and provide proof |
| Template rejected | Too many variables, missing brand name, wrong category | Rewrite with fixed text, add brand, choose correct category |
| Message fails with template mismatch | Sent text differs from template | Match fixed text exactly, including spaces and punctuation |
| Message with a link fails | URL not whitelisted | Register the domain and use the same domain in messages |
| All traffic fails after a provider change | PE-TM chain not updated | Bind the new provider in the chain before switching |
How DND Teams helps
We help businesses across India, from our base in Bhopal to clients in Mumbai, Delhi and Bengaluru, with the complete DLT journey: document checks, header selection, template writing in English and Hindi, URL whitelisting, chain binding and testing. We also review existing templates to find wrong categories before they cause blacklisting. See our bulk SMS services or our India SMS compliance overview for the wider rules.
DLT rules continue to evolve, so check the latest TRAI directions or ask your provider before major campaigns. The steps above reflect our understanding as of October 2026.
Get a custom quote
Working with clients in India, the US, UK, Canada, Australia and the UAE, DND Teams replies with a short written review and a clear quote, with no obligation. Get a custom quote for DLT registration, headers and templates for your business, or message us on WhatsApp at +91 88274 09728.
Not ready for a full project? Start with our SMS pilot for US$79 (one-time, paid in advance). Price covers our setup work only. Platform, message and carrier charges are billed separately at cost. Need more? Get a custom quote. See how our pricing works for what affects your price.
Prices shown are indicative ranges in US dollars and exclude taxes and third-party charges (such as Meta or carrier fees, billed at cost) unless stated. Your price depends on your requirements; get a custom quote for an exact figure. This article is general information, not legal advice, and reflects our understanding as of October 2026.