DLT Sender ID / Header Format Checker
Check whether your transactional Sender ID follows the standard 6-character alphabetic format. Promotional headers are numeric and allocated by your operator, so we explain that separately rather than pretending to validate it.
What is a Sender ID / DLT header?
A Sender ID (also called a header) is the short code your recipients see instead of a phone number. Every header used to send SMS in India must be registered on the DLT platform against your entity, and each is mapped to specific approved templates. India uses two different header formats depending on the message category.
Transactional: the 6-character alphabetic rule
Transactional and service headers must be exactly 6 characters long, using only letters A to Z, with no numbers, spaces, or special characters, such as SMSGWC. This is a hard technical requirement enforced by telecom operators; a header that does not fit this format will be rejected before it even reaches content review.
Promotional: numeric, operator-allocated
Promotional headers work differently. Instead of a business proposing its own alphabetic code, operators allocate a numeric header from a shared pool via the DLT platform. Because a business doesn't define this format itself, there's nothing meaningful to self-check before registration; the header is issued to you rather than submitted by you.
Frequently Asked Questions
Indian DLT headers and Sender IDs must be exactly 6 alphabetic characters, with no numbers, spaces or special characters. For example, SMSGWC is a valid 6-character alphabetic header.
Not for transactional or service headers, which must be purely alphabetic. Promotional headers are the exception: they are numeric by design, allocated by your telecom operator rather than proposed by your business, so this tool doesn't attempt to format-check them.
No. This tool checks the standard 6-character alphabetic format rule only. Final approval also depends on availability, your registered entity name, and your telecom operator or DLT platform review.
No. The check runs entirely in your browser using JavaScript. Nothing you enter is sent to or stored on our servers.
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