TRAI Mandates Sender ID Suffix in SMS – Effective from 6-May-2025

Published by: TextGuru.in

The Telecom Regulatory Authority of India (TRAI) has announced a key update regarding SMS headers for all domestic A2P (Application to Person) traffic. From 6th May 2025, all A2P SMS sent within India will display a suffix at the end of the sender ID (also known as Header/CLI).

Why This Change?

This move is intended to improve transparency, making it easier for recipients to identify the nature of the message — whether it is promotional, service, or transactional.

What is Changing in SMS Headers?

• Suffix Addition: A code will be added to your existing header (e.g. -P, -T).


• Based on Template: The suffix is linked to the message template registered on DLT.


• No Manual Effort: This is done automatically by the operator via DLT mapping.

DLT Suffix Mapping Table

Example:

If your existing sender ID is TXTGUR and you are sending a Transactional message, the updated header will appear as:

TXTGUR-T

Who Is Affected?

• All domestic A2P SMS traffic in India


• Organizations using DLT-registered headers


• Marketing, Educational, Banking, and E-Commerce platforms

What Should You Do?

No changes are required in your DLT account or SMS platform. Just ensure your team is aware of the new format in which headers will appear on user phones.

Still Not DLT Registered?

If you haven’t completed your DLT Registration yet, now is the right time! It’s mandatory to send A2P SMS in India via DLT-compliant headers and templates.

Need help?

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? Email: [email protected]

? Website: www.textguru.in