A2P

A2P, or application-to-person messaging, refers to the delivery of messages from an application or service to a mobile user. It is distinct from P2P (person-to-person) messaging, where the user initiates the conversation. A2P messages are typically business communications and can travel over SMS, MMS, and newer channels such as RCS and various over-the-top platforms, including messaging services routed through apps like WhatsApp or Facebook Messenger in some regions.

Common use cases for A2P messaging include one-time password (OTP) verification, account alerts, transactional notifications, appointment or delivery reminders, and promotional messages where the user has opted in. A2P communications are often automated and triggered by events in a business system rather than by a human user.

Implementation and delivery considerations involve sender identities such as short codes for high-throughput campaigns, long codes for person-like messaging, and toll-free numbers in certain regions. Messages may be routed through direct connections to mobile carriers or via messaging aggregators, with throughput, latency, and pricing varying by channel and country. Channels differ in features and restrictions, with some offering richer content through MMS or RCS and others emphasizing broad reach via SMS.

Regulatory and privacy considerations are also central to A2P. Opt-in and opt-out requirements, clear sender identification, and adherence to regional anti-spam and data protection rules (such as TCPA in the United States or GDPR in the European Union) are commonly enforced to protect consumers and ensure legitimate use.