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What has to be registered
Four things, in order. The entity — your business, verified against corporate documents. The sender ID, called a header in India, which must relate to your registered brand. The template — the exact message text, with variable fields marked, for each message you intend to send. And the consent trail for promotional traffic. Each is approved separately, and traffic is matched against the approved template at delivery time.
Why messages fail after registration
The most common failure is a template mismatch: the message you send must correspond to an approved template, with only the declared variables differing. An extra full stop, a changed word order, or a URL that was not in the approved text is enough for the operator to reject it. The second most common is header–template mismatch, where a valid template is sent under a header it was not registered against.
Promotional versus transactional
India separates traffic types strictly. Transactional and service messages tied to an existing relationship may deliver at any hour. Promotional traffic is restricted by time window and is subject to the recipient's preferences recorded in the DLT system — a subscriber can block promotional categories outright. Sending promotional content on a transactional header is a compliance breach, not a routing accident.
Practical timelines
Entity and header registration typically takes a few business days once documentation is right; template approval is faster but is where most iterations happen. Plan template registration ahead of a campaign rather than alongside it, and register variants — different languages, different lengths — before you need them. Keep the approved template text in version control alongside the code that renders it, so a copy change cannot silently break delivery.