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November 2026 · Vobiz Team SMS marketing is the direct line to your customer’s pocket — a text message that arrives in seconds, gets read within 3 minutes, and requires no app, no internet, and no algorithm to reach them. At 90–98% open rates, SMS outperforms every other marketing channel. Done right — with proper consent, relevant content, and regulatory compliance — it’s one of the highest-ROI channels available.
Key takeaways
  • SMS open rate is 90–98% vs 20–25% for email — messages are read within minutes
  • India requires DLT registration before sending any commercial SMS — no exceptions
  • Promotional SMS goes to opted-in numbers only; transactional SMS can go to all numbers
  • Sending hours: 9am–9pm only (TRAI rule); no Sunday/holiday promotional SMS
  • Vobiz SMS API handles bulk sending, DLT-compliant templates, delivery reports, and opt-out management

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Promotional vs Transactional SMS

The fundamental distinction in Indian SMS marketing: The misclassification risk: labelling a promotional message as transactional to bypass DND filters. TRAI audits for this — penalties include number blacklisting and fines. Use the correct category for your content.

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Why SMS Marketing Works

Immediacy: SMS delivers in under 10 seconds to any mobile phone, anywhere in India, regardless of internet connectivity. Reach: 100% of mobile numbers receive SMS — no smartphone required, no app to install. Open rate: 90–98% of SMS messages are opened, almost all within 3 minutes of receipt. Email open rates average 20–25%. Click-through rate: SMS links achieve 10–30% CTR vs 2–5% for email. Cost efficiency: At ₹0.10–0.20 per message, reaching 10,000 customers costs ₹1,000–2,000 — less than a single Google Ads click for competitive keywords. No algorithm: Unlike social media or email, SMS is not subject to inbox filtering or platform algorithm changes. If you have a valid number and permission, your message gets through.

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India SMS Marketing Regulations (TRAI)

India has some of the world’s most structured SMS regulations. Non-compliance doesn’t just risk penalties — it results in messages being blocked at the carrier level.

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DLT Registration (Mandatory)

TRAI’s Distributed Ledger Technology platform requires:
  1. Entity registration: Your business must register as a principal entity on the DLT platform (Vodafone Idea, Jio, Airtel, BSNL, or TRAI-authorised operators). One-time process, usually free.
  2. Header registration: Your SMS sender ID (e.g., VOBIZ, ACMECR) must be registered. Business SMS cannot use a 10-digit mobile number as sender ID.
  3. Template registration: Every SMS template you send must be pre-approved. The template text must match what you actually send — only variables (name, amount, OTP) can differ.
Unregistered SMS or unregistered templates are blocked by all Indian carriers. No exceptions. See the DLT registration guide.

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NDNC / DND Rules

The National Do Not Call registry (also called DND) blocks promotional SMS to opted-out numbers. TRAI mandates:
  • Scrub your contact list against NDNC before every promotional campaign
  • Do not send promotional SMS to DND-registered numbers
  • Provide an opt-out mechanism in every promotional message (reply STOP)

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Sending Hours and Days

Sending promotional SMS outside these windows results in carrier-level blocking and TRAI complaints.

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SMS Marketing Campaign Types

Promotional campaigns Flash sales, seasonal offers, product launches, event invitations. Best practices:
  • Keep it under 160 characters (one SMS)
  • Include a clear call to action with a short link
  • Personalise with the customer’s name when available
  • Send at optimal times: 11am–1pm and 6pm–8pm show highest engagement
Example:
Transactional alerts OTPs, order confirmations, shipping updates, payment receipts. These are expected by customers — high open rate is guaranteed. Example:
Appointment reminders Reduce no-shows by 30–50% with a reminder 24 hours and 1 hour before the appointment. Example:
Payment reminders EMI due dates, invoice reminders, subscription renewals. Effective alternative to calling for smaller amounts. Customer feedback / NPS Post-purchase survey with a short link. Response rates are 2–3× higher than email surveys. Winback campaigns Re-engage inactive customers with a time-limited offer after a defined period of inactivity.

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Sending SMS with the Vobiz API

Vobiz provides a programmable SMS API for sending individual and bulk messages with delivery receipts and opt-out management. Send a single SMS:
Send a bulk broadcast: Use Vobiz’s broadcast API to upload a recipient list, preview the campaign, and schedule delivery. The API handles:
  • NDNC filtering (automatic DND scrub on promotional campaigns)
  • Delivery reports per message
  • Opt-out tracking (STOP replies automatically added to suppression list)
  • Template variable substitution ([Name], [Amount], [OTP])
Track delivery: Every sent message returns a messageUuid. Poll the message status endpoint or receive real-time delivery webhooks.

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SMS Marketing Best Practices

1. Get explicit consent: For promotional SMS, capture consent at signup, purchase, or via keyword opt-in (“Text JOIN to 56789”). Keep consent records. 2. Personalise: Even just the first name increases response rates by 15–20%. Pull data from your CRM at send time. 3. Time your sends: Avoid Monday mornings and Friday evenings. Best windows: Tuesday–Thursday, 11am–1pm and 6–8pm. 4. Keep it short: One SMS = 160 characters. Longer messages split into multiple parts and cost more. Write tightly. 5. Clear CTA: One action per message. “Shop now”, “Confirm your appointment”, “Track your order” — not all three. 6. Easy opt-out: Every promotional message must include “Reply STOP to opt out”. Vobiz handles STOP responses automatically. 7. Test before sending: Send to a test group of 100 numbers before the full send. Check rendering, link tracking, and delivery rate. 8. Measure: Track delivery rate (aim > 95%), open rate (use link tracking), and conversion rate (UTM parameters on links).

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SMS vs WhatsApp vs Email

SMS wins on reach and urgency. WhatsApp wins on richness and engagement for opted-in users. Email wins on cost for lower-urgency content.

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Next Steps