SMS Header Registration in India

1. The rules at a glance

2. Promotional headers and category digits

Vi's header registration manual ties the first digit of a numeric promotional header to the customer-preference category, the same categories people choose when they set DND preferences:

3. Choosing a header that gets approved

The registrar's question is simple: would a customer reading this header recognise your business? Headers that pass usually come straight from the name on your PAN or GST certificate:

Register separate headers for separate purposes if it helps your customers, for example one for OTPs and one for order updates, but it is not required. One header can serve several templates.

4. What registrars refuse

• Other people's names and brands: trademarks you don't own, registered company names that aren't yours, celebrity and politician names.
• Government look-alikes: anything resembling a government department, scheme or a SEBI-regulated body, unless you are that body and submit proof.
• Generic words that could belong to anyone, such as OFFERS, SCHOOL or ALERTS.
• Obscene or misleading words.
• Headers with no evidence when the link to your business isn't obvious. A website page, trademark certificate or letterhead usually settles it.

5. How a header looks on the phone

Recipients don't see the bare six characters. They see a prefix, the header and, since May 2025 according to SMS providers, a category suffix:

VM-AVNZON-S     service message via an operator/circle coded "VM"
JM-AVNZON-T     transactional (e.g. an OTP)
AD-AVNZON-P     promotional
XY-ABCDEF-G     government

The prefix depends on the operator and circle that carried the message, so the same header can appear with different prefixes. Your application only ever sends the six-character header; operators add the rest. The suffix is useful for customers, who can now see at a glance whether a message is a promotion.

6. How to register a header

1. Get your entity approved first. Headers hang off your entity (PE) ID; the DLT registration guide covers that step.
2. In your operator portal, open header registration and choose the type: transactional, service or promotional (or "other" on Vi).
3. Enter the six-character header and, if asked, the reason it relates to your business.
4. Attach supporting proof if the link to your name is not obvious.
5. Submit. Vi and BSNL publish a registrar target of 60 minutes for headers. Allow a working day or two in practice.
6. Register content templates against the approved header, with every variable tagged by type.

Portal-specific screens are covered in our guides to Jio, Airtel, Vi and BSNL.

7. Keeping your header

• Use it. Vi and BSNL return headers unused for more than 90 days to the pool, and Airtel suspends headers for no usage. A school that only sends during admissions should keep a small amount of regular traffic on its header.
• Renew the entity. Headers stop working when the entity registration lapses.
• Keep the chain declared. Your SMS provider (telemarketer) must be bound to your entity. Messages through an undeclared chain have been rejected since 11 December 2024.
• Re-verify when asked. Airtel runs periodic header and template verification; Jio asks for annual self-certification.

8. Checking who owns a header

TRAI's SMS Header Information portal lets anyone look up which registered entity a header belongs to. It is the quickest way to check whether a message claiming to be from your bank or a delivery company is genuine. BSNL and Vi also publish daily PDF lists of registered headers on their DLT portals.

For senders it is a useful pre-check too: if the header you want is already registered to someone else, choose another before you submit.

Sending from code? The header goes in the sender_id field of the API call. See our PHP or Python guides, and DLT error codes for header-template mismatches. For which route each message belongs on, read transactional vs promotional SMS.