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Messaging Registration

CarrierX messaging

To protect users from spam and unwanted messages, mobile carriers require the registration and vetting of applications that send messages to individuals, known as A2P (Application-to-Person) messaging. This process allows carriers to identify message senders and monitor message content. CarrierX will help you understand the requirements to streamline the registration and review process.

Common Requirements​

Regardless of the number type you choose, there are some common requirements to keep in mind:

Opt In​

For most message types, recipients must opt-in before receiving messages. The recipient must confirm that they understand what they will be receiving. Your registration should include a detailed description of how users opt in to receive your messages. This opt-in process may also be referred to as a Call to Action.

Required Responses​

Your application must be able to receive and respond to two types of keyword messages from users: STOP and HELP. You must have systems in place to properly handle these messages before registering.

  • STOP​

    If a user sends the keyword STOP (or a similar keyword) to your phone number, you are required to stop sending messages to that user. You may send a confirmation message informing the user that they will no longer receive messages. Unless the user explicitly opts in again, you must not send any further messages to them.

  • HELP​

    If a user sends the keyword HELP (or a similar keyword), your application should respond with a message that includes:

    • The program or brand name.
    • Additional customer care contact information (e.g., a phone number or email address).
    • Instructions on how to opt out or stop receiving messages.
Sample HELP Response​
Made Up Company
Contact customer support at 800-555-1212
Text STOP to stop all messages
Msg&Data rates may apply

Use Case Description​

Provide a clear description of the content subscribers are signing up to receive or the purpose of the messages.

Sample Message​

Provide samples of the text and media messages sent to recipients. If your campaign includes multiple message types, supply samples for each type.