SMS Marketing in India: DLT Registration and TRAI Rules Explained

To send business SMS in India legally, you must register your company as a Principal Entity on a telecom operator’s DLT platform, get your sender headers and every message template approved, and send only to people whose consent you hold. This guide covers the DLT registration process step by step, how header and template approval works, the consent rules under TRAI’s TCCCPR regulations (including the 2025 and 2026 amendments), and how to run SMS campaigns that actually get delivered.

What DLT Registration Is and Why It Exists

India’s commercial SMS system runs under the Telecom Commercial Communications Customer Preference Regulations, 2018 (TCCCPR), framed by the Telecom Regulatory Authority of India. To control spam, TRAI required telecom operators to run blockchain-based DLT platforms where every business sender, sender ID, message template and telemarketer is recorded.

When your SMS provider pushes a message, the operator checks it against the ledger: Is the sender registered? Is the header approved and linked to this sender? Does the text match an approved template? Is the recipient eligible to receive this category of message? If any check fails, the message is dropped. That is why so many small businesses see “SMS sent” in their panel but nothing arrives on the customer’s phone.

Who needs to register

• Any business sending OTPs, order updates, appointment reminders or payment alerts
• Any business sending offers, discount codes or event invitations by SMS
• Schools, clinics, coaching centres, housing societies and NGOs that send bulk SMS through a gateway
• Software companies whose apps send SMS on behalf of their clients (the client is usually the Principal Entity)

Personal SMS from your own phone to a few contacts is not covered. The moment you use a bulk SMS gateway or API, DLT applies.

The roles in the system

Role	Who it is	What it does
Principal Entity (PE)	Your business	Owns headers and templates, holds customer consent, is accountable for content
Telemarketer (TM)	Your SMS provider or aggregator	Delivers messages to operators; must be linked to your PE ID
Access Provider	Jio, Airtel, Vi, BSNL and others	Runs the DLT platform, scrubs and delivers messages
Customer	The recipient	Sets preferences (DND), gives or revokes consent, can complain

DLT Registration Step by Step

You only need to register as a Principal Entity on one operator’s DLT portal. Your registration is shared across the ledger. Each major operator runs its own portal, and your SMS provider will usually tell you which one it prefers.

Step 1: Keep your documents ready

• Business PAN card
• Proof of business: GST registration certificate, Certificate of Incorporation, Udyam registration, Shop and Establishment licence or similar
• ID proof of the authorised signatory
• A letter of authorisation on letterhead if someone other than the owner or director is registering (portals usually provide a format)
• An official email ID and a mobile number for OTP verification

Step 2: Register as a Principal Entity

1. Open the operator’s DLT portal and choose “Enterprise” or “Principal Entity” registration.
2. Select your entity type (proprietorship, partnership, LLP, private limited, government, trust and so on).
3. Enter business details exactly as they appear on your PAN and GST documents. A mismatch between the name on the form and the document is the most common reason for rejection.
4. Upload documents and pay the registration fee.
5. Wait for approval, then note your PE ID (Entity ID). You will need it for everything that follows.

Fee: Several provider guides put the Principal Entity registration fee at about Rs 5,900 including GST (Rs 5,000 plus 18% GST) on major portals, while others say charges vary by operator. Sources also disagree on whether registering on a second operator costs extra. Check the current fee on the portal before you pay, and you normally need to register on only one.

Time: Approval typically takes a few working days, depending on the operator and how clean your documents are.

Step 3: Register your headers (sender IDs)

A header is the name customers see, such as “AB-SHOPZY-S”. You register the brand part; the operator adds the prefix and the category suffix.

• Choose a header that clearly relates to your brand name. Headers that look like another company’s brand get rejected.
• Register separate headers if you send both promotional and service traffic, and select the right category for each.
• Upload proof that you own the brand or trade name if the header does not match your registered business name.

Step 4: Register content templates

Every SMS you send must match an approved template. Fixed text stays fixed; anything that changes per message (name, order number, amount, date) goes into a variable placeholder, written as {#var#} on most portals.

Example of a service template:

Dear {#var#}, your order {#var#} for Rs {#var#} has been dispatched and will reach you by {#var#}. Track: {#var#} – SHOPZY

Rules that save you rejections:

• Choose the right category. Promotional for offers; service for messages about something the customer has bought or applied for; transactional is narrow and mainly used for OTPs and similar critical messages.
• Do not hide promotions in service templates. A delivery update that adds “Get 20% off your next order” is promotional. This is the misuse TRAI has repeatedly cracked down on.
• Whitelist links and numbers. TRAI has directed that URLs, APK links, OTT links and callback numbers used in messages must be whitelisted. Register your domains and short links with the template; non-whitelisted links are blocked.
• Keep variables tight. Use only as many variables as you need, and never make the whole message a variable.
• Add your brand name at the end of each template.

Step 5: Link your telemarketer

Inside the DLT portal, add your SMS provider as a telemarketer (or approve its request). Then give the provider your PE ID, header IDs and template IDs. Every message you send through its panel or API must carry the correct IDs.

Headers, Suffixes and Number Series Explained

In February 2025, TRAI amended the TCCCPR so that message headers carry standard suffixes. According to TRAI’s press release of 12 February 2025, customers can identify the message type from the header itself:

Suffix	Category	Typical use
-P	Promotional	Offers, discounts, sale announcements, new launches
-S	Service	Order and delivery updates, appointment reminders, account alerts
-T	Transactional	OTPs and critical transaction messages
-G	Government	Messages from government bodies

The suffix is added by the system, so you do not type it, but it means customers now know at a glance when you are selling to them. Write promotional messages that are worth reading.

The same amendment restricted the use of ordinary 10-digit mobile numbers for telemarketing. Promotional voice calls use the 140 series, and the 1600 series is designated for transactional and service calls. If your sales team cold-calls from personal mobile numbers, that is a compliance risk.

Consent Rules You Must Follow

Consent is where most small businesses get into trouble, because they collect numbers casually at the billing counter and then send promotions to everyone. Here is how it works.

DND and preferences

Customers can block commercial communication through the Do Not Disturb (DND) preference, set by calling or sending SMS to 1909 or through their operator’s app. Promotional messages are not delivered to customers who have blocked that category unless you hold their explicit consent recorded under the system.

Key consent rules from the 2025 amendment

• 7-day validity for transaction consent. Consent given by a customer for completing an ongoing transaction is valid for only 7 days.
• Implicit consent ends with the contract. For transactional and service messages, implied consent lasts only for the duration of the contract with the customer. After that, you need explicit consent to keep messaging.
• 90-day wait after opt-out. You cannot ask a customer who has opted out for consent again for 90 days, though the customer can opt in at any time.
• Mandatory opt-out in promotions. Promotional messages must give customers an option to opt out.

What changed in the September 2026 Third Amendment

TRAI notified the Telecom Commercial Communications Customer Preference (Third Amendment) Regulations, 2026 on 18 September 2026. Most provisions come into force 30 days after publication in the Official Gazette, some after 60 days, and the items in its Annexure after 90 days. Points that matter for a small business sender:

• Consent is now defined more precisely as a voluntary permission for a specific purpose, product or service, and the regulation states that nothing in it exempts a sender from obligations under the Digital Personal Data Protection Act, 2023.
• Explicit consent must be verifiable and recorded through the consent registration framework, including consent you collected earlier outside it.
• Service messages about an ongoing purchase that need explicit consent: that consent is valid for 7 days or until revoked, and the customer can renew it for further 7-day periods.
• “Relationship” is time-bound: an enquiry counts only if made within the 7 days before your message, and an application within the previous three months, and you must keep the enquiry in verifiable form.
• Faster action on misused headers and templates: operators must suspend a misused header or template within six hours of noticing it, and the sender must reset passwords and API keys and file a police complaint within set deadlines before it is restored.

The regulation is long and technical. Ask your SMS provider how it is implementing each change, and read the official text for anything your business depends on. Rules change, so treat this guide as a starting point, not legal advice.

Penalties for spam

Under the 2025 amendment, if a sender crosses the complaint threshold (five complaints in ten days), all its telecom resources can have outgoing services barred for 15 days on the first violation. Repeat violations can mean disconnection of all telecom resources across operators for one year and blacklisting. Customers can now complain within 7 days of receiving spam. A single careless campaign to an old, unconsented list can shut down the SMS and calling lines your whole business runs on.

How to Collect Consent the Right Way

• At the counter or checkout: add an unticked checkbox, “Send me offers and updates by SMS”. Keep a record of who ticked it and when.
• Missed-call or keyword opt-in: “Give a missed call to receive our weekly offers.” Store the date and time.
• On your website: a separate opt-in field, not buried in terms and conditions.
• Keep promotional and service lists separate in your CRM or billing software.
• Honour opt-outs within your own system immediately, even before the operator processes them.

Writing SMS That Get Read

A standard SMS segment holds 160 characters in English (GSM-7 characters). Messages in Hindi, Gujarati or other Indian scripts use Unicode, which allows only 70 characters per segment, so the same message costs more. Use a free word and character counter to check length before you submit a template.

Do	Do not
Lead with the benefit: “Flat Rs 200 off on orders above Rs 999”	Open with “Dear Valued Customer, Greetings from…”
Include one clear action and one whitelisted link	Add three links and a phone number
Mention an end date for offers	Use false urgency every week
Send at sensible hours, around shop timings	Send late at night
Sign off with your brand name	Leave the customer guessing who sent it

For example, a dental clinic in Indore might send a service reminder: “Hi {#var#}, your cleaning appointment is on {#var#} at {#var#}. Reply or call {#var#} to reschedule. – SmileCare Clinic.” It is useful, expected and clearly not a promotion.

Keep SMS for short, time-sensitive messages. Bigger announcements such as a new branch or product launch need a fuller story on your website, social media and in the press; our guide on writing a press release in India covers that format.

Troubleshooting Delivery Problems

Symptom	Likely cause	Fix
Panel shows sent, customer gets nothing	Template text does not match the approved version exactly	Compare character by character, including spaces and punctuation
All messages fail	Wrong PE ID or template ID in API calls	Recheck IDs with your provider
Messages with links fail	Domain or short link not whitelisted	Whitelist the URL with the template
Promotions reach only some customers	Recipients on DND without recorded consent	Expected; collect proper consent
Header suspended	Misuse or complaints	Contact the operator, fix the cause, follow remedial steps

Frequently Asked Questions

Is DLT registration mandatory for small businesses?

Yes, if you send commercial SMS through any bulk SMS service or API. Size does not matter; unregistered headers and templates are blocked.

How much does DLT registration cost?

Provider guides commonly quote about Rs 5,900 including GST for Principal Entity registration, but operators can differ and fees change. Confirm on the DLT portal before paying.

Do I need to register with every operator?

Generally no. You register as a Principal Entity on one operator’s portal, and your details are shared on the ledger. Your SMS provider will tell you if it needs anything else.

What do -P, -S, -T and -G mean at the end of a sender name?

They show the message category: promotional, service, transactional and government. TRAI introduced these suffixes through its February 2025 amendment to the TCCCPR.

Can I send promotional SMS to customers on DND?

Only if you hold their explicit consent recorded under the system. Otherwise promotional messages to customers who have blocked them will not be delivered, and complaints can lead to penalties.

How long does template approval take?

Usually from a few hours to a few working days, depending on the operator. Rejections are mostly due to wrong category, too many variables or links that are not whitelisted.

Set It Up Once, Then Keep It Clean

DLT registration feels like paperwork, but it is a one-time effort: register your entity, get two or three good headers, and build a small library of clean templates for your common messages. After that, the real work is consent. Collect it properly, keep promotional and service lists apart, honour opt-outs fast and keep an eye on TRAI’s latest amendments. Do that and your SMS will reach customers instead of disappearing into the filter.