A2P messaging
Application-to-person SMS — messages sent by software to a person, rather than between two people.
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Application-to-person SMS — messages sent by software to a person, rather than between two people.
A2P stands for application-to-person. It covers any SMS originated by software rather than typed by a human: one-time passcodes, appointment reminders, delivery notifications, and marketing campaigns.
Carriers treat A2P traffic differently from person-to-person messaging. It is subject to registration requirements, throughput limits, and content filtering, and it is usually billed at a different rate. Sending A2P volume over channels meant for P2P traffic is a reliable way to get blocked.
A2P only works against numbers that can actually receive SMS. Landlines cannot, and some VOIP numbers cannot depending on the provider, so every undeliverable number in a list is both wasted spend and a negative signal against the sender reputation.
Related terms
- 10DLC — The US carrier framework for sending registered application-to-person SMS from a 10-digit local number.
- SMS deliverability — The proportion of sent SMS messages that are actually delivered to a recipient handset.
- Opt-in — A recipient explicitly granting permission to be contacted by call or text.