A2P use case best practices and onboarding guidelines


Arturo Garcia


References for implementation

Although these best practices do not offer legal advice or guidance (we’re not your lawyers, so consult with your lawyers if there are any legal questions), all messages sent are required to comply with all relevant laws and regulations, including (but not limited to) the FCC Telephone Consumer Protection Act (TCPA). For more information on industry guidelines, please see the CTIA Messaging Principles and Best Practices.

Also useful to understanding A2P use case best practices is understanding Short Code requirements. The Short Code Monitoring Handbook gives a more detailed explanation of implementing some CTIA best practices.

Best practices for A2P use cases over Toll-Free SMS

The following list includes best practices and a minimum set of guidelines for customers sending A2P use cases over toll-free phone numbers.




The consumer must give appropriate consent

The single most important practice is ensuring you have accurate, reliable consumer opt-in specific to the type of messages you’re sending consumers. It’s expected that opt-out rates will be consistently low when you have obtained reliable and clear consumer opt-in consent. At anytime, Bandwidth or the wireless carriers may request from you evidence of written opt-in consent for a particular message.

If opt-out rates exceed 0.5%* in a 24 hour period for a particular campaign or number, you can expect to complete a consent audit to prove that your campaign is in compliance and appropriately collecting opt-in. If a campaign or number receives opt-outs in excess of 4%*, the campaign or number in question may be suspended and an RCA and consent audit will be required.

*The daily opt-out rate is defined as the total number of unique consumer phone numbers divided by the unique opted out consumers that were sent messages in a 24 hour period.

Single Number Use

Utilize single number for identity

Each campaign should use one primary phone number. Using a single number for both text and voice calls is recommended. Avoid spreading messages across multiple source phone numbers, specifically to dilute reputation metrics and evade filters. This is referred to as snowshoeing” and can result in your content being blocked. If your messaging use case requires the use of multiple numbers to distribute “similar” or “like” content, please discuss with your on-boarding team.

Identify Brand

Identify the brand or business in the body of the message

Your application, service, or business name should be included in the content of the body. For example: “Your Business Name: ​You have an appointment for Tuesday 3:00PM, reply YES to confirm, NO to reschedule. Reply STOP to unsubscribe”

Support for STOP

Use of Opt-Out language

The best practice is notifying the consumer of their ability to opt-out from future messages from the message sender. This is especially important when sending informational or promotional messages. An example would be to include the sentence, “Reply STOP to unsubscribe” to the end of the initial message sent to the consumer, or “reply STOP to cancel”. Best practice is to use the word "reply" before the stop keyword.

Processing STOP

Keywords ensuring proper functioning of Opt-Out behavior - STOP  keywords

Consumer opt-in and opt-out functionality is enforced at the network level via the STOP and UNSTOP keywords. This functionality cannot be disabled for service providers or message senders.

Message senders have obligations to process the opted-out consumer phone number so it is removed from all distribution lists and is logged as “opted out” from SMS communications. This ensures that future messages are not attempted and consumer consent is honored.

Examples of valid opt-out messages: “STOP” “Stop” “stop” "ARRET" "Arret" "arret"

For toll-free SMS, there is no need to send an acknowledgement to the consumer. The opt-out confirmation message returned to a consumer is generic and gives instructions on how to opt back into service again with the message sender’s phone number.

Opt-out confirmation message:

NETWORK MSG: You replied with the word "STOP" which blocks all texts sent from this number. Text back "UNSTOP" to receive messages again.


Processing Opt-In Keywords specific to Toll Free Texting

A consumer can opt back in at any time to receive messages by texting the keyword “UNSTOP” or "START" to a message sender’s phone number. The keyword is not case sensitive and triggers an opt-in only when sent as a single word, with no punctuation or leading spaces (any trailing spaces are trimmed). If the consumer uses the opt-in keyword within a sentence an opt-in is not triggered.

Examples of valid opt-ins: “UNSTOP” “Unstop” “unstop” "START" "Start" "start" "DEBUTER" "Debuter" "debuter"

The message returned to a consumer is generic and informs the consumer they can start two-way texting with the message sender’s phone number again.

Message text:

NETWORK MSG: You have replied "unstop" and will begin receiving messages again from this number.

Single Domain

Associate URL

Each campaign should be associated with a single web domain. Although a full domain is preferred, a URL shortener may be used to deliver custom links. Avoid public/shared domain shorteners, such as goo.gl or bit.ly.

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