Glossary Compliance
What is A2P messaging?
Also called application to person, business sms, bulk sms
A2P, application-to-person, messaging is any text sent by software rather than typed by a human: appointment reminders, delivery notifications, one-time passcodes, marketing. It is distinguished from P2P, person-to-person, messaging, and carriers treat the two very differently in terms of registration, filtering and price.
Consent is the part that gets businesses into trouble
The rules that matter most are about permission. Recipients must have agreed to receive messages, the agreement must be recorded, and opting out must work immediately and permanently. Handling STOP correctly is not optional and is not something to implement later. The penalties for getting this wrong are regulatory rather than merely reputational.
Choosing the route
A2P traffic can run over 10DLC long codes, toll-free numbers or short codes. Long codes suit ordinary business volumes and are the cheapest to set up. Toll-free messaging is a middle option with its own verification. Short codes carry the highest throughput and the highest cost, and only make sense at genuine scale.
Message segments, and why a long text costs more
A message is billed by segment rather than by message. Plain GSM characters give you 160 per segment, but a single emoji or a curly quote switches the whole message to Unicode and drops that to 70. Multi-segment messages also carry header overhead, so the second and subsequent segments hold slightly less. The practical effect is that a message that looks marginally over the limit can cost double, and that pasting text from a word processor, which silently substitutes typographic quotes, is a reliable way to double your bill.