Send transactional SMS that reaches customers any hour

Transactional and service-implicit messages are a direct response to a customer action or a fact about their account: an OTP for a login, a confirmation that an order shipped, a balance after a transaction, an appointment that is about to start. Under DLT these categories are exempt from DND scrubbing and time-of-day rules, because they aren't marketing — a password reset has to go through at 2am.

You send them the same way as any SMS: one HTTP call with a registered transactional header, the principal entity ID, and the template ID for that message. We validate the template against the registry before dispatch, so a promotional sentence slipped into a transactional template fails fast rather than being scrubbed after you've paid for it.

Every message returns a delivery receipt on your webhook, with retries and operator failover, so you can reconcile a confirmation against the event that triggered it. Unicode is supported, so a confirmation can go out in Hindi or a regional language, and long messages are concatenated and receipted per part.

Getting the category right at registration is the whole game. A genuinely transactional message in a transactional template reaches everyone; the same words in the wrong category get rejected or scrubbed. Our DLT guide covers how the categories are decided.