Every business sending SMS in India must choose the correct message route — transactional or promotional. Choosing the wrong one is not just a compliance issue; it can result in messages being blocked before they ever reach your customers. This guide breaks down every key difference so you can make the right choice for your use case.
What the TRAI Says About SMS Categories
TRAI (Telecom Regulatory Authority of India) classifies all commercial SMS into two broad categories under the Telecom Commercial Communications Customer Preference Regulations (TCCCPR):
- Transactional — messages that serve an existing customer relationship or respond to a customer action
- Promotional — messages sent for the purpose of selling products, services, or offers
The category determines which telecom route your message travels, who it can reach, and when it can be sent.
Side-by-Side Comparison
| Feature | Transactional SMS | Promotional SMS |
|---|---|---|
| Purpose | OTPs, alerts, service messages | Marketing offers, campaigns |
| DND delivery | Yes — bypasses DND filters | No — blocked for DND numbers |
| Allowed hours | 24×7 | 9 AM – 9 PM only |
| Sender ID format | 6-letter alphanumeric (e.g., GCMDIA) | 6-letter alphanumeric |
| DLT registration | Required | Required |
| Pricing | Slightly higher per SMS | Lower per SMS |
| Delivery priority | High (priority carrier queue) | Standard queue |
Transactional SMS — When to Use It
Qualifying Message Types
Under TRAI guidelines, a message qualifies as transactional if it:
- Is triggered by a customer-initiated action (login attempt, purchase, password reset)
- Delivers information the customer has a right to receive (account alert, policy update)
- Contains no promotional content whatsoever
Examples that qualify:
Your OTP is 847291. Valid for 10 minutes. Do not share it. — BANKCOOrder #ORD-7821 has been dispatched. Track at: example.com/track — SHOPCODr. Sharma appointment confirmed for 15 Jun at 11:00 AM. — CLINIX₹5,000 debited from your account ending 3421. If not you, call 1800-XXX. — HDFCBK
Key Advantage: DND Exemption
The most significant advantage of the transactional route is DND exemption. In India, over 300 million numbers are registered on the Do Not Disturb (DND) registry. Promotional SMS cannot reach any of these numbers. Transactional SMS can — because TRAI recognises that customers need to receive critical service communications regardless of their DND preference.
This makes the transactional route essential for OTPs, banking alerts, and any message where 100% recipient coverage is required.
Promotional SMS — When to Use It
Qualifying Message Types
A message is promotional if its primary intent is to drive a commercial action — a sale, sign-up, or visit — rather than deliver a service obligation.
Examples that qualify:
FLAT 40% OFF on all products this weekend only! Shop now: example.com — SHOPCOExclusive offer for you: Get 3 months free on our premium plan. Upgrade today. — SAASCONew collection just dropped. Be the first to shop. Visit our store. — BRANDX
Timing Restriction: 9 AM – 9 PM Only
TRAI prohibits promotional SMS outside the 9 AM to 9 PM window (IST). Messages scheduled or triggered outside these hours are either blocked or held until the window opens, depending on the SMS provider's configuration.
This restriction protects consumers from late-night and early-morning marketing messages.
DND Registry Impact on Reach
Before running any promotional campaign, your effective audience is your contact list minus all DND-registered numbers. In India, this can reduce deliverable reach by 30–50% for consumer-facing databases.
Plan your campaign volumes accordingly and never attempt to route promotional content through the transactional path — TRAI's scrubbing system detects template mismatches and blocks the message.
The DLT Requirement — Applies to Both
A common misconception is that only promotional SMS needs DLT registration. Both routes require it.
What You Must Register
- Entity — your company's legal identity on an approved DLT portal (Jio, Airtel, Vi, BSNL, etc.)
- Sender ID (Header) — the 6-character alphanumeric that appears as the sender name
- Message Template — the exact content of each SMS you plan to send, with variables declared
Separate Headers for Each Route
TRAI requires different sender IDs for transactional and promotional messages. You cannot use the same header on both routes. Register separate headers during DLT setup.
Template Matching Is Enforced
When your message is sent, the telecom operator compares it against your registered template. Any mismatch — even a single extra word or a changed punctuation mark — results in the message being scrubbed before delivery.
Pricing Difference
Transactional SMS typically costs slightly more per message than promotional SMS. This reflects the higher infrastructure priority — transactional messages are dispatched via dedicated carrier queues with lower latency and higher delivery guarantees.
| Route | Typical Price Range (India) |
|---|---|
| Transactional | ₹0.09 – ₹0.15 per SMS |
| Promotional | ₹0.07 – ₹0.12 per SMS |
Prices vary by volume, provider, and contract terms. Both routes require a minimum commitment in most plans.
Can One Message Be Both?
No. TRAI does not recognise a hybrid category. If your message contains any promotional content — a discount, an offer, a call-to-action to buy — it must travel as promotional, even if it also contains service information.
Wrong approach: Embedding a "₹500 off your next order" message inside an order confirmation — this is promotional content and should be sent as a separate promotional SMS (to non-DND numbers only, during allowed hours).
Right approach: Send the order confirmation as transactional, and if you want to promote a follow-up offer, send a separate promotional message to eligible non-DND contacts.
Choosing the Right Route: Decision Checklist
Use this checklist before sending:
- Is this message triggered by a customer action or a service obligation? → Transactional
- Does the message contain any discount, offer, or call-to-buy? → Promotional
- Must the message reach DND numbers? → Transactional only
- Will the message be sent outside 9 AM – 9 PM? → Transactional only
- Is this a bulk marketing campaign to a cold or opted-in list? → Promotional
- Is this an OTP, banking alert, or delivery update? → Transactional
Summary
The core distinction is intent and customer relationship. Transactional SMS serves the customer; promotional SMS markets to them. Choose transactional for OTPs, alerts, and service messages where delivery to every recipient (including DND) is non-negotiable. Choose promotional for campaigns, offers, and announcements, keeping timing restrictions and DND reach limits in mind.
Both routes require DLT registration. Get Click Media supports both with complete DLT assistance, separate sender IDs, and carrier-grade infrastructure for each route.
Frequently Asked Questions
Transactional SMS delivers critical, service-related messages (OTPs, alerts, order updates) and can be sent to all numbers including DND-registered ones, 24×7. Promotional SMS delivers marketing content and can only reach non-DND numbers between 9 AM and 9 PM.
No. Promotional SMS is blocked by telecom operators for DND-registered recipients. Only transactional SMS — sent via the approved transactional route — bypasses DND filtering under TRAI regulations.
TRAI restricts promotional SMS to the window of 9 AM to 9 PM IST. Messages scheduled outside this window are either blocked by the operator or queued until the allowed window begins, depending on the platform.
Yes. Both categories require TRAI DLT registration — entity, sender ID (header), and message template must all be pre-approved before any commercial SMS can be sent in India, regardless of the route.
