Quick Answer
A DLT template checker compares the SMS you plan to send with its approved DLT template. Only the {#var#} parts may change, each up to 30 characters; every other character, space and punctuation mark must match exactly, or operators block the message. Paste both below to see the first difference and the variable values.
How to use the DLT template checker
Paste the approved template
Copy it exactly from your DLT portal, including {#var#} placeholders, spaces and punctuation.
Paste the SMS
Use the final text your system will send, with real values in place of each {#var#}.
Read the result
A match lists every variable value. A mismatch marks the first differing character and the likely reason.
Check the header and links
Confirm the header format and that every link and call-back number is whitelisted for that header.
Common reasons a DLT message is rejected
Operators compare every SMS with the template registered for its template ID. These are the usual causes of a block.
- Fixed text changed: a word, a full stop or a capital letter differs from the approved template.
- Extra, missing or double spaces, or a line break that is not in the template.
- Curly quotes, long dashes or the rupee sign pasted from a document instead of the approved characters.
- A variable value longer than 30 characters, such as a long link or address.
- A URL, app link or call-back number that is not whitelisted for the header.
- Wrong template ID or header sent with the message, or a header not linked to the template.
- Promotional words in a service template, or a promotional SMS to a DND number.
- Whole message in one variable ({#var#} only) - most operators reject such templates.
DLT template categories
| Category | Use it for | Header | DND numbers |
|---|
| Transactional | OTPs and transaction alerts from banks and financial institutions | 6 letters | Delivered |
| Service Implicit | Updates to existing customers: orders, deliveries, bookings, payments, OTPs | 6 letters | Delivered |
| Service Explicit | Messages to customers who gave recorded consent, including offers | 6 letters | Delivered with valid consent |
| Promotional | Offers and marketing to anyone who has not opted out | 6 digits | Not delivered; 10 AM - 9 PM only |
Recipients see the header with an operator prefix (for example VM-SGHUBS) and, under the 2025 TRAI rules, a category suffix such as -S, -T, -P or -G.
Frequently Asked Questions
What is a DLT template?
A DLT template is the approved text of an SMS that a business registers on an operator DLT portal in India. The fixed text stays the same in every message; the changing parts, such as names, amounts or OTPs, are marked as {#var#} variables.
How many characters can one {#var#} hold?
Up to 30 characters per {#var#}. If a value is longer, such as a long link or address, use two variables in the template or shorten the value, for example with a short link.
Why is my SMS blocked when the template is approved?
Usually because the sent text differs from the approved template: an extra or missing space, changed punctuation, a different word, a value longer than 30 characters, or a link or call-back number that is not whitelisted for the header.
Which header do I use for promotional SMS?
Promotional SMS go out from a 6-digit numeric header. Transactional and service messages use a 6-letter header that represents your brand.
Is this checker an official DLT approval?
No. It is a helper that applies the common matching rules. Final template approval and message scrubbing are done by the operator DLT portals, which may apply further checks.
Are my templates stored?
No. The check runs entirely in your browser; your template and message are not sent to our servers.
Get your DLT templates right the first time
Our team registers entities, headers and templates with you and keeps your SMS flowing.