A DLT template ID is the number an Indian operator's DLT platform assigns to each approved SMS text, and a DLT header is the registered sender ID. Every commercial SMS to India must carry a registered header, the template ID and the sender's entity ID, and its text must match the approved template, or it is blocked during scrubbing.
Rules last checked: October 2026.
What is a DLT template ID?
A DLT template ID is the unique identifier of a content template: the fixed wording of a message, with placeholders for the parts that change, approved under a category and linked to one or more headers. When you send, your SMS provider passes the template ID and your entity ID (PE ID) with the message, and the operator checks the text against the template. This page goes deeper into templates and headers; the full registration process, including chain binding and DND, is in our main guide to India DLT registration.
What is a DLT header?
A DLT header is the sender ID registered under your entity for a category. The format depends on the category:
| Category | Header format | Suffix shown on the phone |
|---|---|---|
| Transactional (bank OTPs and bank alerts) | 6 characters, usually letters | -T |
| Service (alerts, non-bank OTPs, notifications) | 6 characters, usually letters | -S |
| Promotional | 6 digits, first digit marks the business category | -P |
| Government | Exempted government headers | -G |
The suffixes come from TRAI's February 2025 amendment to the commercial communications regulations and have appeared on handsets since May 2025. They are added automatically from the template category; you do not add them yourself. Category rules are covered in transactional vs promotional SMS.
How to register a DLT template
- Register the entity on one operator DLT portal and get your entity ID.
- Register headers for the categories you need.
- Write the template: the full message text, with each changing part replaced by the variable placeholder {#var#}. Operators commonly allow up to 30 characters per variable.
- Pick the category and link the header. Service templates have been split on most portals into implicit (no consent needed, linked to an existing relationship) and explicit (consent based).
- Whitelist links. Since 1 October 2024 only whitelisted URLs, APK links and OTT links may appear in messages.
- Submit and record the template ID once approved, then give it to your SMS provider.
Also make sure the entity is bound on DLT to the provider that delivers your traffic. Since 11 December 2024, messages with a missing or mismatched sender-to-telemarketer chain are rejected.
Why are DLT templates rejected?
- Promotional content inside a service or transactional template. Since the 2025 amendment, such a message counts as promotional.
- Variables covering most of the text, so the template does not fix any real wording.
- No brand or entity name in the text.
- Links that are not whitelisted, or link shorteners not registered.
- Header and template in different categories.
At sending time, the most common errors are a missing or invalid template ID, a missing entity ID, an unapproved header, and text that differs from the template (extra spaces, changed punctuation, a variable longer than allowed). Map these to the codes your provider returns using SMPP error codes and SMS DLR status codes.
DLT templates for OTP messages
OTPs from banks go under transactional headers; other OTPs go under service. Keep one template per use (login, payment, password reset), put the code in a variable, and keep the rest fixed. Avoid links in OTP templates. See OTP SMS best practices for wording that works.
Getting an India SMS route
VoIPMatcher sources A2P SMS routes from its carriers and manages them for you, for both domestic DLT traffic and international traffic to India. See the India SMS destination page, then request an India SMS route with your entity ID, headers and volume.
Frequently asked questions
What is a DLT entity ID?
The entity ID, also called the Principal Entity ID or PE ID, is the unique number a business receives when it registers on an Indian operator's DLT platform. It identifies the sender behind every header and template. The entity ID must be passed with every message, together with the template ID, or operators reject it.
Can I use the same DLT template on all operators?
Yes. DLT platforms of the Indian operators share registration data, so an entity, header or template registered on one portal is recognised across networks. You register once, on the portal of your choice, and give your SMS provider the entity ID, the headers and the template IDs to use.
Is DLT registration free?
It depends on the portal. Some operator DLT portals charge a one-time fee for entity registration, while others have offered it free; we could not confirm a single official fee. Header and template registration are part of the same account. Check the current fee on the portal you choose before you start.
Can I send SMS in India without a DLT template?
No. Commercial SMS to Indian numbers that does not match a registered header and an approved template is blocked during operator scrubbing. Routes that claim to deliver without DLT registration are non-compliant and unreliable. Register the entity, headers and templates, or use a provider that registers them for you as a telemarketer.
What does DLT template approval depend on?
Approval depends on the template matching its category, using the right header, containing the brand name, using variables only for parts that change, and including only whitelisted links. Templates that are vague, hide promotional content in a service message, or use variables for almost the whole text are commonly rejected.
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