An SMS sender ID, called a header on DLT, is the short brand name or number that appears as the sender of your message. You register it on your operator DLT portal against your Principal Entity ID, and it must match your business. Approval typically takes one to three days, and templates can only be attached to an approved header.
By Rohit Jadhav. Last reviewed 25 October 2026. This is operational guidance, not legal advice. Portal rules differ, so confirm header requirements on your operator's portal.
Open your phone's inbox and look at who your bank, your courier and your pharmacy are in the list. Each appears as a short name, such as a few letters and a dash. That name is the sender ID, and registering it is one of the steps in DLT. This guide explains what an SMS sender ID is, how to choose and register one, and why headers are rejected. It is part of our main guide to DLT registration in India. For help with the set-up, Nexcomm's bulk SMS service includes header approval and template submission. More guides sit under Compliance & Regulations.
What is an SMS sender ID?
An SMS sender ID is the name or number a recipient sees as the sender of a commercial SMS. In TRAI's regulation it is called a header, defined as an alphanumeric string of up to eleven characters or numbers assigned to an individual, business or legal entity to send commercial communications. The recipient can also tell the type of message from the end of the header: "-P" for promotional, "-S" for service, "-T" for transactional and "-G" for government messages.
In practice, Nexcomm's team registers brand headers of six characters, for example a short form of the brand name. The portals and operators decide the exact format they accept, so confirm it when you apply.
How do you register a sender ID?
- Get your Principal Entity ID first. A header belongs to a registered business. See the steps in the main guide.
- Log in to the DLT portal and open the header registration section.
- Enter the header and map it to your brand name.
- Submit and wait. Approval typically takes one to three days.
- Load the approved header into your SMS provider's dashboard.
Registration for the business is covered in DLT registration for a proprietorship and for a private limited company. What the operator charges is in DLT registration charges.
How should you choose a header?
- Use the name people know. A customer who sees an unfamiliar sender may ignore or report the message.
- Keep it short and readable. Six clear characters beat a long string.
- Match your business name or brand. The portal compares them.
- Avoid names that look like a bank, a government body or another brand. They will be rejected, and they are risky.
- Plan for categories. You may want different headers for transactional and promotional messages.
Do promotional and transactional headers differ?
They can. Reports on how the system works say promotional headers are numeric, while transactional and service headers can be alphabetic brand names (see the MediaNama report on template and header rules). Check with your provider which header type your message category uses. We explain categories in transactional vs promotional SMS.
Why are headers rejected?
The usual reasons are a name that does not match the business, a name that resembles another brand or an institution, or a documentation mismatch on the Principal Entity. When a header is rejected, read the stated reason, correct the application and resubmit rather than trying a random alternative. Also remember that one template links to only one header, so plan your template list around your headers. See DLT template rejected for the other side.
What happens when links or numbers are in the message?
A header is only part of the check. If your message contains a link, an APK or a call-back number, that item must be registered separately, as we explain in URL whitelisting on DLT.
A worked example (hypothetical)
A diagnostic lab called "Sunrise Health Labs" applies for the header "SUNRIS". This is an invented example. The first request is for "HEALTH", which the portal rejects because it is generic and does not match the business name. The lab resubmits "SUNRIS" with the brand name mapped, and it is approved in two days. It then registers two templates against the header: a report-ready alert and an appointment reminder. Customers see a familiar short name instead of a random number.
Common mistakes with sender IDs
- Choosing a generic word. It does not match the business.
- Copying a bank or government style name. It is rejected and can cause trouble.
- Registering the header before the Principal Entity. It cannot be done.
- Linking one template to several headers. A template links to one header only.
- Changing headers often. Customers lose recognition.
- Forgetting to load it into the provider's dashboard. The platform cannot send with it.
Frequently asked questions
What is a header in DLT?
A header is the registered sender ID for your SMS, the name or number recipients see. The regulation defines it as an alphanumeric string of up to eleven characters or numbers assigned to a business to send commercial communications.
How many characters can an SMS sender ID have?
The regulation allows up to eleven characters or numbers. In practice, brand headers of six characters are what Nexcomm's team registers. Confirm the format on your portal.
How long does sender ID approval take?
Typically one to three days after your Principal Entity is approved. Rejections add time, because you correct and resubmit.
Why was my sender ID rejected?
Most often because the name does not match your business, looks like another brand or an institution, or the Principal Entity details do not match. Read the reason and resubmit with a corrected name.
Can I use my company name as the header?
Usually yes, in shortened form if the portal limits length. Use the name customers know, and keep it consistent across your messages.
Sources checked
All checked on 25 October 2026.
- TRAI, consolidated Telecom Commercial Communications Customer Preference Regulations, 2018 (definition of header; header suffixes)
- MediaNama: TRAI on SMS template rejection (September 2025) (header types; news report)
- Operator DLT portals: header format and timelines as supplied by Nexcomm's team; confirm on the portal
If you are choosing a sender ID and want a second opinion, you can reach our team through the contact page.