Alert21 Guide
What Is an SMS Sender ID or DLT Header?
A sender/header is the registered identity associated with the business communication and displayed/represented to the recipient according to telecom rules and message type.
Why Sender Identity Matters
A consistent, approved sender helps recipients identify the organization responsible for the communication and lets telecom systems validate the message against the registered entity/template relationship.
Sender ID in Alert21
The recommended Alert21 SMS API does not require the customer to send sender_id on every request when the Template ID is already mapped to the correct sender/header. This reduces configuration errors and keeps route selection centralized.
Common Mistakes
- Using an unapproved header.
- Mapping a template to the wrong header.
- Trying to imitate another brand.
- Using one sender across unrelated entities without authorization.
- Assuming international alphanumeric sender behavior is the same as India DLT.
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