How sender headers and template IDs work
Every outbound SMS carries a six-character header and a 19-digit template ID that both have to match your DLT record.
Operators (Jio, Airtel, Vi, BSNL) reject any SMS whose header or template ID isn't registered for your Principal Entity on the DLT chain. SMSLocal validates both at the moment of send so you don't waste credits on a message the operator will drop.
Fields that must match exactly
- Header (sender) — six uppercase letters, e.g. SMSLCL. Case-sensitive on some operators.
- Template ID — a 19-digit numeric string assigned by the DLT portal at approval.
- Body — must match the approved text character-for-character. Variables in {#var#} slots can be anything; static text cannot.
- Category — transactional, service, or promotional must match what you registered.
If the DLR comes back with 'template mismatch' or 'header suspended', 95% of the time it's an extra space or a changed word in the body. Diff the send payload against the approved template and you'll find it.
Browse other help categories
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Create your SMSLocal account, add INR credits to your wallet, complete DLT registration, and send your first compliant SMS, WhatsApp, or OTP in under fifteen minutes.
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OTP & Transactional
Priority routing to the fastest carrier, automatic retry and failover logic, idempotency keys to prevent double-sends, and WhatsApp OTP fallback when SMS is slow or fails.
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