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SMS Compliance and A2P 10DLC in the US

A2P 10DLC is designed to increase trust across the messaging ecosystem. One part of creating this trust in SMS messaging relates to registration to provide transparency about who is sending messages and what types of messages they are sending. The other part of building trust is ensuring that people have provided consent for that messaging. User consent to receive messages is not just good practice, it is required by carriers and Twilio’s messaging policies.

SMS compliance can be confusing. To provide clarity around SMS regulations, guidelines, and policies, this section describes the Federal Communications Commission’s (FCC) Telephone Consumer Protection Act (TCPA), the Cellular Telecommunications Industry Association’s (CTIA) messaging principles and best practices, Twilio’s Acceptable Use and Messaging Policies, and finally how all of this relates back to A2P 10DLC.

Before we dive into the details, here are the key things to know:

  • Organizations using 10-digit local phone numbers to send SMS through Peer-to-Peer (P2P) platforms are required to register under A2P 10DLC.
  • Consent and revocation of consent are required as described in Twilio’s messaging policy as well as U.S. carrier requirements.
  • There are no exceptions to Twilio’s messaging policy or A2P 10DLC for political, emergency, or other 10DLC Special Use Case campaigns.
  • After registering for A2P 10DLC, you should experience decreased filtering when sending compliant messages due to the increased transparency provided by brand and use case registration.


Rulings and regulations implemented by the Federal Communications Commission (FCC) may relate to specific requirements based on federal law, while carriers and communication platforms may have more stringent policies for sending communications through their networks and services. This discrepancy between federal law and the policies of individual carriers and communication platforms has created confusion in the messaging ecosystem. 

For example, in June 2020, the FCC issued a Declaratory Ruling that addressed “peer-to-peer” text messaging in the context of the Telephone Consumer Protection Act (TCPA). In the context of this ruling, peer-to-peer text messaging refers to a type of messaging in which organizations either use a software application to send two-way text messages between an individual sender and recipient, or in which two people exchange text messages from their personal devices. Note that this definition is different from that used by the U.S. carrier ecosystem in which all text messages sent using a software application are defined as A2P messaging.

The FCC decided that peer-to-peer messaging platforms that lack the capabilities of an autodialer, or use of pre-recorded messages as defined by the TCPA, would not be required to adhere to consent requirements outlined in the TCPA. However, This ruling created some confusion in the messaging ecosystem regarding what consent is required for sending consumers text messages. 

As noted previously and as with other rulings, this FCC ruling relates to the minimum requirements based on federal law, while carriers and communication platforms -require more stringent adherence to consent-based messaging practices. 

Consent and revocation of consent are required as described in Twilio’s Messaging Policy. U.S. carriers also require user consent to send messages. Following these guidelines will help ensure that your messages are delivered to your recipients. Learn more about messaging compliance and opt-in.

CTIA Messaging Principles and Best Practices

In 2019, the Cellular Telecommunications Industry Association (CTIA), the trade association representing wireless carriers in the U.S., released the latest version of its messaging principles and best practices. This document outlines messaging practices that facilitate a healthy messaging ecosystem of wanted messages between businesses (and nonprofits) and consumers. Among key tenants of these principles and best practices are obtaining explicit opt-in and honoring opt-out from the people you are messaging. This opt-in must relate not only to your organization as the sender, but the specific campaign use case for which you are messaging.

U.S. carriers determine what messages are delivered to their customers, the end consumer. Failure to abide by the CTIA messaging principles and best practices can result in message filtering and phone number blocking by carriers. 

Twilio Messaging Policy

Twilio’s Messaging Policy, which is central to our Acceptable Use Policy, is consistent with CTIA messaging principles and best practices, and requires consent and revocation of consent. This policy is designed to support a healthy, sustainable messaging ecosystem for businesses, organizations, and consumers to engage in messaging.

Again, note that the consent requirements defined by the CTIA and Twilio’s Messaging Policy are in addition to the minimum requirements defined by the TCPA. In other words, consent requirements for sending SMS messages through carrier networks exceed what may be legally allowable under TCPA. 

All organizations should ensure that your audience has provided consent to receive text messages for each of the campaign use cases for which you are sending messages. There are no exceptions to Twilio’s policies or A2P 10DLC for political, emergency or other 10DLC special use case customers.

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