Transactional SMS

A transactional SMS is a message tied to the service being delivered, not to its promotion: appointment confirmation, visit reminder, delivery information, tracking link. It's sent within an existing relationship, generally on the basis of the contract rather than a marketing opt-in — that's what distinguishes it from marketing SMS, and what lets it be useful at any useful hour.

For a service business, it's the backbone of customer communication: everything about the appointment lives by text — confirmation, reminder, preparation ("plan for basement access"), follow-up. Its discipline is that of information: factual, brief, expected. The moment a transactional message slides into promotion — an offer slipped into a reminder — it moves into the marketing regime, with its consent requirements.