What A2P SMS is and how it differs from P2P: the messaging businesses use

A2P is the technical term for text messages sent by systems to people: codes, alerts, campaigns. Here is how it differs from person-to-person SMS and why using legitimate routes matters.

Definition

A2P stands for Application-to-Person: text messages that a system, an application or a platform sends to people. The code that arrives when you sign in, the bank alert, the delivery notice, a retailer campaign: all of that is A2P. P2P, Person-to-Person, is the ordinary SMS between two handsets.

The distinction is not merely semantic. Mobile operators treat the two traffic types differently, with their own routes, rates, rules and filters. Understanding the difference avoids delivery and compliance problems.

How A2P works technically

An A2P message does not leave a handset. It leaves a system that connects to a messaging platform through an API; the platform in turn connects to the operator message centres (SMSC) over SMPP, a protocol designed to send and receive large volumes of SMS between systems. The operator receives the message, locates the subscriber, delivers it and returns a delivery report.

This path enables what P2P cannot: volumes of thousands of messages per minute, branded sender IDs or short codes, per-message delivery reports, and security controls such as token authentication and encryption. We describe the whole journey in the article on what happens when an SMS is sent.

Why operators separate the two traffic types

Operators size and price their networks for personal use. Bulk business traffic, if it ran over P2P routes, would saturate resources and open the door to spam and fraud. That is why they require A2P traffic to come in over dedicated connections, with identified providers, registered senders and rules on content and volume.

Using P2P routes for business traffic, known as grey routes (SIM farms sending thousands of messages from handsets, for example), is prohibited by the operators. Messages sent that way are filtered, blocked or arrive with random senders, and they put the company that buys them at risk.

What to check when buying A2P messaging

• That the provider has direct connections with the operators in Mexico, not resold or grey routes.
• That it offers delivery reports (DLR) per message and per operator.
• That it supports registered senders: alphanumeric, short code or long number, as the case requires.
• That it operates under the IFT guidelines with formal contracts and invoicing.
• That the API has security controls: token, authorised IPs, optional encryption.
• That it separates transactional from promotional traffic.

Grupo Tecnophone has been running A2P messaging in Mexico over direct operator connections for more than a decade, for banking, fintech, retail and government.

A2P in numbers and trends

A2P traffic keeps growing, driven by authentication (OTP) and transactional notifications, even as messaging apps expand. The reason is structural: SMS is the only channel that reaches any handset with no app and no data plan, which makes it indispensable for verifying identities and for critical communications. Operators, in turn, have tightened filters against illegitimate traffic, which makes direct routes and registered senders more valuable than ever.

If your company sends or plans to send SMS from its systems, take a look at the enterprise SMS messaging platform or request a demo.

Frequently asked questions