In India, every commercial SMS belongs to a category, and the category decides who you can send it to, when you can send it, and how it appears on the customer's phone. Since February 2025, the category is even visible in the sender name: TRAI's amendment to the Telecom Commercial Communications Customer Preference Regulations (TCCCPR) requires headers to carry a suffix of -P, -S, -T or -G.
Getting the category right matters. TRAI has directed that content templates registered under the wrong category will be blacklisted, and repeated misuse can lead to suspension of a sender's services. This guide explains each category in plain English, with examples, so you can register templates correctly the first time.
Why categories exist
TRAI's framework is built around customer preference. Customers can block promotional messages entirely, or block certain types of promotions, through the national Do Not Disturb (DND) preference system, using the TRAI DND app, their operator's app or the 1909 short code. Service and transactional messages, which customers generally need, are treated differently.
If a business could label marketing as "service", customers' DND choices would be meaningless. That is why operators check categories carefully and why TRAI treats miscategorised templates as a serious violation.
The four categories at a glance
| Category | Header suffix | Typical purpose | Reaches DND customers? |
|---|---|---|---|
| Promotional | -P | Offers, discounts, launches, event invitations | No, unless the customer has given explicit consent through the operator process |
| Service | -S | Order updates, reminders, account information, confirmations | Yes for service implicit; service explicit needs recorded consent |
| Transactional | -T | OTPs and alerts linked to a transaction the customer has just made, especially for banks | Yes |
| Government | -G | Messages from government bodies | Treated as its own category |
The suffix categories come from the TRAI regulation of 12 February 2025 and the PIB summary of the amendment. Your provider and operator determine the precise rules for which sender types may use each category.
Promotional SMS (-P)
Promotional messages are anything that encourages the customer to buy, visit, sign up or try something. Examples:
- "Diwali sale: 30% off all sarees till Sunday. Visit our Arera Colony store."
- "New batch for NEET coaching starts 5 Nov. Book a free demo class."
- "Flat ₹500 off your next service visit. Use code SERVICE500."
Rules to remember:
- Promotional messages are not delivered to customers who have blocked promotions through DND, unless the customer has given explicit consent through the operator's digital consent process.
- They can only be delivered during the permitted daytime window, generally 10 AM to 9 PM.
- Under the 2025 amendment, operators must provide an opt-out option in promotional messages so customers can stop receiving them more easily.
If a message contains any offer, discount or invitation to buy, treat it as promotional, even if it is sent to existing customers.
Service messages (-S)
Service messages relate to a product or service the customer already uses or has asked for. They are split into two kinds.
Service implicit messages follow naturally from the customer's existing relationship with you and do not need separate consent. Examples:
- "Your order #45812 has been shipped and will arrive by Friday. Track: [whitelisted link]"
- "Reminder: your appointment with Dr Sharma is tomorrow at 11:30 AM."
- "Your electricity bill of ₹{amount} is due on {date}."
Service explicit messages are service-type messages that are not strictly needed for the existing relationship, so they require the customer's explicit, recorded consent. For example, a bank might send information about a new feature to customers who agreed to receive such updates. The consent is registered against a consent template on DLT.
The key test for service implicit: would the customer reasonably expect and need this message because of something they bought, booked or applied for? If the message is really trying to sell something new, it is not a service message.
Transactional messages (-T)
The transactional category is the narrowest. It is mainly used for OTPs and alerts that confirm a transaction the customer has just carried out, such as a banking debit alert or a one-time password for a payment. Historically, the transactional category was restricted mostly to banks and similar regulated entities, while other businesses send OTPs and alerts under service implicit. Your provider can tell you which category applies to your business type.
An OTP template might look like:
"{#var#} is your OTP to log in to MyShop. Valid for 10 minutes. Do not share it with anyone. -MyShop"
Government messages (-G)
The 2025 amendment created a separate category for messages sent by government bodies, so that customers do not miss important public communications. If you are a government department or agency, your provider will guide you through the registration requirements.
Common mistakes we see
Adding an offer to a service message. "Your order has shipped. Use code SAVE10 on your next order!" turns a service message into a promotional one. Send the offer separately as a promotional message.
Registering marketing as service implicit to reach DND customers. This is exactly what TRAI's blacklisting rule targets. It may work briefly, but the risk to your headers and templates is not worth it.
Using one template for multiple headers. TRAI's August 2024 direction says one content template cannot be linked to multiple headers. Register templates against the header they will be used with.
Forgetting links and call-back numbers. URLs, APK links and call-back numbers in messages must be whitelisted; messages with non-whitelisted links are not delivered.
Sending promotions late at night. Promotional messages outside the permitted window will not be delivered, so schedule campaigns within it.
How to choose the right category: a quick decision guide
- Is the message an OTP or an alert about a transaction the customer just made? If yes, it is transactional or service implicit, depending on your entity type.
- Is it an update about something the customer already bought, booked or applied for, with no sales content? If yes, it is service implicit.
- Is it service-type information that goes beyond the existing transaction? If yes, it is service explicit, and you need recorded consent.
- Does it promote, sell, invite or offer anything? If yes, it is promotional.
- Are you a government body sending public communication? If yes, use the government category.
When in doubt, choose the more restrictive category. A promotional template that reaches fewer people is far better than a blacklisted service template.
Should you use SMS, WhatsApp or both?
Categories also matter when you plan your channel mix. Many businesses use SMS for OTPs, reminders and critical alerts, because it works on every phone without an app, and use WhatsApp for richer conversations and campaigns. WhatsApp has its own template categories (marketing, utility and authentication) and its own rules. Our comparison of bulk SMS vs WhatsApp marketing in India covers the trade-offs.
How DND Teams can help
DND Teams is based in Bhopal and works with businesses across India. We audit existing templates for category risks, rewrite them so they are approved and deliver reliably, and set up separate headers for service and promotional traffic. If you are starting from scratch, our DLT registration guide explains the registration steps, and our bulk SMS services page explains how we work.
This article is general guidance based on TRAI publications as of October 2026. Rules change, so confirm category requirements with your operator or provider before major campaigns.
Get a custom quote
Working with clients in India, the US, UK, Canada, Australia and the UAE, DND Teams replies with a short written review and a clear quote, with no obligation. Get a custom quote for reviewing your SMS templates and categories, or message us on WhatsApp at +91 88274 09728.
Not ready for a full project? Start with our SMS pilot for US$79 (one-time, paid in advance). Price covers our setup work only. Platform, message and carrier charges are billed separately at cost. Need more? Get a custom quote. See how our pricing works for what affects your price.
Prices shown are indicative ranges in US dollars and exclude taxes and third-party charges (such as Meta or carrier fees, billed at cost) unless stated. Your price depends on your requirements; get a custom quote for an exact figure. This article is general information, not legal advice, and reflects our understanding as of October 2026.