SMS marketing in India: compliance, DLT registration, and what actually works

SMS marketing in India is both an effective channel and one of the most regulated. TRAI (Telecom Regulatory Authority of India) introduced the DLT (Distributed Ledger Technology) framework in 2021, and businesses that ignored it found their messages blocked. By 2023, compliance is non-negotiable. But within the rules, SMS remains one of the highest-reach marketing channels available to Indian businesses.

Understanding the DLT framework

DLT is a blockchain-based system introduced by TRAI to curb spam SMS and protect consumers. All businesses that send commercial SMS messages in India must register on the DLT platform of one of the telecom operators (Vodafone Idea, Airtel, BSNL, Reliance Jio, MTNL, Tata, or BSNL).

Registration involves submitting your business's PAN, GSTIN, and registration certificate. Once registered, you get a Principal Entity ID. You also need to register your Sender ID (the 6-character alphanumeric name that appears in the "From" field of your SMS, like MYNTRA or HDFCBK) and your Message Templates.

Every message template you send commercially must be pre-registered. If your live message does not match the registered template (even by a few words), it may get blocked. This is a significant change from the free-form SMS campaigns that were common before 2021.

The practical compliance checklist

Register on the DLT portal of your SMS provider (most Indian SMS providers like MSG91, Textlocal India, Kaleyra, or ValueFirst have their own DLT portal and can walk you through registration). The registration fee is typically around ₹5,000 to ₹10,000 for entity registration, though some operators offer it free.

Register all Sender IDs you plan to use. Each brand variant may need a separate Sender ID. Get these approved before you need to send; approval takes 1 to 3 business days.

Register every message template you plan to use. Use variables (marked with {#var#}) for the parts that change per recipient, like customer name, order number, or discount code. The fixed parts of your template must match exactly what you send.

Maintain a consent database. TRAI requires that recipients have explicitly consented to receive promotional SMS. Keep records of when and how consent was collected. For transactional messages (OTPs, order confirmations), consent requirements are different and less strict.

Writing SMS that converts within the character limit

Promotional SMS in India are capped at 160 characters per message (longer messages are charged as multiple SMS). This requires precision. Every word must earn its place.

The most effective promotional SMS structure: a clear offer upfront, the benefit in specific terms (₹500 off, 20% discount), a short link, and an opt-out instruction. Example: "Get 20% off all mobiles this weekend. Shop now: bit.ly/abc123. Reply STOP to opt out."

Use a URL shortener for links. Bit.ly or your own branded short domain (which most SMS providers support) keeps links short while allowing click tracking. Knowing which SMS campaigns drove clicks is essential for measuring ROI.

Timing matters in India. SMS sent between 10 AM and 12 PM and between 6 PM and 8 PM typically have higher engagement. Avoid early morning and late evening. Avoid sending during major religious observances unless your message is contextually relevant.

What SMS is still good for in 2023

OTPs and transactional alerts: SMS OTPs are still the standard in India for two-factor authentication and payment verification. This is not going away. Every business that handles sensitive transactions should have SMS OTP infrastructure.

Time-sensitive promotions: a flash sale notification or a limited-time offer can reach an opted-in list within minutes. For events like a one-day sale or an appointment reminder, SMS is faster to read than email and more intrusive than WhatsApp (which can be muted).

Reaching less-digitally-active audiences: some Indian customers, particularly in older demographics or rural markets, are more reliably reachable via SMS than via WhatsApp or email.

Frequently asked questions