Definition: A2P (application-to-person) messaging is text messaging sent by a business or organization through a software application to a person's phone.

When your dentist's system texts you a reminder, that is A2P. When your friend texts you back, that is person-to-person (P2P). The phone network treats these two kinds of traffic differently, and A2P comes with more rules.

What is A2P called in the CTIA guidelines?

CTIA's Messaging Principles and Best Practices (May 2023) replaced the 2019 version. It uses two main labels:

You will still see "A2P" everywhere, including in provider product names like Twilio's A2P 10DLC.

What rules apply to A2P messages?

CTIA sets out these expectations for non-consumer senders:

• Get consent before messaging, and express written consent for marketing.
• Make opt-out easy and honor it at any time.
• Do not use rented, sold, or shared opt-in lists.
• Keep a clear privacy policy that is easy to find.

Why it matters for your website

To send A2P texts on 10DLC numbers, you register a brand and campaign, and reviewers look at your website. It should show your business, your privacy policy, your SMS terms, and how people opt in. See the 10DLC website requirements.

Related terms: 10DLC, Opt-in, STOP and HELP keywords, Campaign use case

Sources

• CTIA Messaging Principles and Best Practices (May 2023)
• Sinch: What is 10DLC?
• Twilio: A2P 10DLC overview

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