A2P SMS

A2P SMS, explained

A2P stands for application-to-person. It covers any text message sent by software to a person rather than typed by another human: verification codes, delivery updates, appointment reminders, fraud alerts and marketing messages. Almost every SMS code you receive at sign-up is A2P traffic. Because A2P messages can be sent in huge volumes, carriers treat them differently from ordinary personal texting. They expect businesses to use approved routes such as short codes, verified toll-free numbers or registered 10-digit long codes in the US, and they filter traffic that looks unregistered or spammy. In the UK and elsewhere, businesses often send A2P messages from an alphanumeric sender name. A2P rules exist to protect people from spam and scams, and they also explain some delivery problems: if a service's messaging route is misconfigured or filtered, its codes may be delayed or dropped regardless of which number you entered. The opposite category is P2P, person-to-person messaging between ordinary phone users.

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