TRAI SMS Rules in 2026: What Every Business Sender Must Do
TRAI has tightened the rules for business SMS and calls every year since 2024. This guide lists each rule now in force, the date it started and what you need to do, so your messages are not blocked.
In 2026 every business SMS in India must come from a DLT-registered entity, header and template, through a declared PE to telemarketer chain. Links, app links and call-back numbers must be whitelisted and tagged in templates. Operators add -P, -S, -T or -G to headers, senders re-certify yearly, and business calls use 140, 1600 or 1601 numbers.
Chain must be declared
Since 11 December 2024, SMS on an undeclared PE to telemarketer path is rejected.
Links must be whitelisted
URLs, APK and OTT links not whitelisted on DLT are blocked since 1 October 2024.
Yearly self-certification
Re-certify your details, headers and templates every year or they are suspended.
Calls have number series
140 for promotions, 1600 for banks and finance, 1601 for other service calls.
The base rules: DLT registration and categories
Under TRAI's Telecom Commercial Communications Customer Preference Regulations (TCCCPR) 2018, every business that sends SMS registers as a Principal Entity (PE) on an operator's DLT portal. It then registers its headers, which are sender IDs, and its content templates. Each message is checked against these records before delivery.
Promotional messages go only to people who have not blocked that category, or who gave consent, and by default only between 10am and 9pm. Service and transactional messages, such as OTPs and order updates, can go at any hour, including to numbers on DND, when they use an approved template. Every promotional message must also carry a way to opt out.
Message traceability: the PE to telemarketer chain
TRAI wants every SMS traceable from the business that sent it to the operator that delivered it. Each PE must declare on DLT the telemarketers (TMs) that carry its traffic and bind that chain. Under directions of August to November 2024, messages on an undeclared or mismatched chain have been rejected since 11 December 2024.
The 2025 amendment caps a chain at two telemarketers: one aggregator and one delivery telemarketer. When you move to a new SMS provider, add its telemarketer ID to your chain on your DLT portal before you switch traffic. Our team gives you the exact ID during onboarding.
Links, app links and call-back numbers
Since a TRAI direction of May 2023, links in SMS must be whitelisted. Enforcement began on 1 October 2024: messages with URLs, APK links or OTT links that are not whitelisted on DLT are blocked. Whitelist the fixed part of each link, such as kovaimart.in/t/. A shortened link is delivered only if its domain is whitelisted too.
A direction of 18 November 2025 added pre-tagging. Each variable in a template must now be marked with its type, such as #url# for a link or #cbn# for a call-back number, so operators can check the value in every message against your whitelist. New templates need the tags straight away, and messages from untagged older templates that fail the check are now rejected.
Header suffixes, self-certification and unused templates
Operators now add a suffix to every SMS header so people can see the type of message: -P for promotional, -S for service, -T for transactional and -G for government. A header like JD-KOVAIM-S tells the reader it is a service message from a registered sender. All operators had put the suffixes in place by July 2025.
Senders and telemarketers must self-certify their registration details, headers, content templates and consent templates every year. Anything not certified is suspended automatically. Headers and templates not used for 90 days are deactivated, so review your list before a seasonal campaign.
Complaints and penalties
The 2025 amendment made complaints easier. Customers can complain within 7 days of a spam call or SMS, with only basic details, and they no longer need to be on DND to complain about an unregistered sender. Operators must act within 5 days.
The penalties fall on the sender. A first violation bars all outgoing services for 15 days. A repeat leads to disconnection of all telecom resources for one year and blacklisting. The third amendment of September 2026 lowers the trigger to 3 complaints in 10 days when the operator's AI systems also flag the sender, and requires misused headers or templates to be suspended within 6 hours.
Business calls: 140, 1600 and 1601 numbers
Ordinary 10-digit mobile numbers may not be used for telemarketing. Promotional calls must come from 140-series numbers. Service and transactional calls from banks, NBFCs, insurers, mutual funds and other regulated financial firms must come from 1600-series numbers, with deadlines between 1 January and 15 March 2026. A 1601 series followed in August 2026 for service calls from other sectors, starting with utilities and logistics.
The 2026 amendment also requires automated calls, such as recorded voice messages and voice OTPs, to be declared in advance.
What to do this month
Check your chain
Log in to your DLT portal and confirm every provider's telemarketer ID is bound to your entity.
Tag your templates
Mark each variable as #url#, #cbn# or another type, and whitelist every link domain.
Self-certify
Re-certify your details, headers and templates before your yearly deadline.
Retire old templates
Remove unused headers and templates and register clean replacements before campaigns.
Frequently asked questions
What is PE TM chain binding in DLT?
It is TRAI's message traceability rule. Each Principal Entity declares on its DLT portal the telemarketers that carry its SMS, in order, and binds that chain. Since 11 December 2024, SMS sent through a chain that is not declared, or does not match, is rejected. A chain may have at most two telemarketers.
Why are my SMS with links being blocked?
The link's domain is probably not whitelisted on your DLT portal, or the template variable that carries it is not tagged as #url#. Since 1 October 2024, operators block SMS with URLs, APK links or OTT links that are not whitelisted. Whitelist the fixed part of the link and tag the variable in the template.
What do -P, -S, -T and -G mean after an SMS header?
They show the message type. -P is promotional, -S is service, -T is transactional and -G is government. Operators add the suffix automatically to your registered header, so you keep registering a 6-character header such as KOVAIM. The suffix helps people tell a genuine business message from spam.
Do I need to renew my DLT registration every year?
Yes. You pay the operator's yearly entity fee, and TRAI now also requires senders to self-certify their details, headers, content templates and consent templates every year. Anything you do not certify is suspended automatically. Headers and templates unused for 90 days are deactivated, so keep your list current.
Can I send promotional SMS at night?
By default, no. Customer preference settings keep promotional messages off between 9pm and 10am unless a customer opts in to other hours. Service and transactional messages, such as OTPs and delivery updates, are not limited by these time bands and can go at any hour with an approved template.
Which number series should my business use for calls?
Promotional calls must use 140-series numbers. Banks, NBFCs, insurers, mutual funds and other regulated financial firms must use 1600-series numbers for service and transactional calls. From August 2026, other sectors, starting with utilities and logistics, are being moved to a new 1601 series. Ordinary mobile numbers may not be used.
Not sure your DLT setup is compliant?
Send us your entity, header and template IDs. We check the chain, tags and whitelists with you, free of service charge.