WhatsApp vs SMS Marketing in India: Rules, Reach and Cost

SMS reaches every phone; WhatsApp reaches people with a richer, two-way message. In India, promotional SMS runs through TRAI’s DLT system, with registered headers and templates, DND preferences and a default delivery window of 10 AM to 9 PM. WhatsApp marketing runs through Meta’s Business API, with approved templates, opt-in from each customer, images, buttons and replies in the same chat.

Neither is “better” for everything. This guide compares the rules, what customers see, how costs work and where each fits, so you can decide what goes on WhatsApp and what stays on SMS.

At a glance

The SMS rules in India (TRAI and DLT)

Commercial SMS in India is governed by TRAI’s Telecom Commercial Communications Customer Preference Regulations (TCCCPR), 2018 and runs on the telecom operators’ DLT (distributed ledger) platforms.

• Register first. Your business (the principal entity), every header (sender ID) and every content template must be registered on DLT. If you collect consent, the consent template is registered too. Since 2025, entity registration also needs physical verification.
• Three categories. Transactional messages respond to a transaction the customer just made, such as an OTP. Service messages go to your own customers about their product or service. Promotional messages advertise, and must carry an opt-out. Adding promotion to a service message makes the whole message promotional.
• Header suffixes. Headers carry a suffix showing the category: -P promotional, -S service, -T transactional and -G government.
• DND preferences. Customers can block promotions entirely or by category (banking, real estate, education, health and more) through 1909 or the TRAI DND app. Promotions with recorded explicit consent still reach them.
• Timing. By default, promotional SMS isn’t delivered between 9 PM and 10 AM.
• Links and numbers. Since 1 October 2024 SMS containing links, APK or app links that aren’t whitelisted on DLT are blocked, and variables in templates must now be tagged and validated.
• Consent withdrawal. If a customer withdraws consent, you can’t ask for it again for 90 days.

The WhatsApp rules

• Opt-in. WhatsApp’s Business Messaging Policy lets you message people who gave you their number and agreed to hear from your business. The opt-in can be collected on your website, in store, by SMS or on a call, as long as it names your business. See WhatsApp opt-in.
• Approved templates. Any message you start must be a template approved by Meta, in a category: marketing, utility or authentication. See WhatsApp template messages.
• 24-hour window. When a customer replies, you can chat freely for 24 hours. See the 24-hour window.
• Quality and limits. Blocks and reports lower your quality rating and can pause templates; Meta also limits how many marketing messages each person receives.
• Customer control. People can stop marketing messages from your business inside WhatsApp, and you must respect it.

What customers see

The same Diwali offer looks very different on each channel:

There’s no official, independent figure comparing SMS and WhatsApp open rates in India, so be wary of round numbers quoted online. Test with your own customers: WhatsApp reports read and reply counts per campaign, which makes that easy.

Cost

SMS is usually cheaper per message, but long messages are split into several parts and links need setup on DLT. WhatsApp marketing templates cost more per message, with Meta’s India rate at about ₹0.86 per delivered marketing message plus your provider’s margin and GST, and utility templates cost far less. Replies from customers are free, and the first 1,000 service replies per number each month are free.

Compare on outcomes, not price per message: replies, orders and bookings per ₹1,000 spent. Rates for WhatsApp are in WhatsApp API pricing in India.

When to use which

Moving campaigns to WhatsApp with Automate AI

Automate AI runs your WhatsApp campaigns, templates, chatbots and shared inbox on Meta’s official API, with live delivered, read and replied counts. Series 2, 3 and 4 also include RCS, rich messages with images and cards for Android phones that support it, from the same campaigns. Keep your existing DLT-registered SMS provider for people who aren’t on WhatsApp. See WhatsApp campaigns and pricing.