SMS Best Practices and the CTIA

To date, most end users exchanging Text Messages are individual wireless consumers, but more recently, exchanges between wireless consumers and other endpoints such as consumers of cloud-based messaging services or enterprises, are becoming more common.

A common assumptions for new customers who just start sending out SMS to their end-users is that all text messages will deliver to their end-users 100% of the time, however this is not true.

Before sending any sort of SMS communications to your customers, it is important to understand what is considered "best practices" and how to use these guidelines in order to ensure best success when sending out text messages to your customers.


The CTIA represents the wireless communication industry and in order to best protect end consumers, they have come up with recommended guidelines and best practices when sending out Text Messages to your end-users.

As of December 2018, the FCC has voted to reclassify wireless text messages as an information service rather than a telecommunications service, which in turn gives the wireless carriers the right to block any text message they do not want on their network. Although one does not need to follow these guidelines the CTIA has outlined, it is highly recommended to follow the guidelines in order to have the best possible delivery rates.

Person-to-Person (P2P)

According to the CTIA guidelines, P2P traffic generally describes the low-volume exchange of wireless messages between end users. Below outlines characteristics and attributes of human operation for the purpose of classifying P2P traffic





Messages/telephone number (TN)/minute

15 to 60 messages per minute

A human is typically not able to originate more than about one message per second.


Messages/TN over time

1,000 per day

Only in unusual cases do humans send more than a few hundred messages in a day, nor can a human send messages continuously over a long period of time.

Unique Recipients

Number of distinct recipients/TN


A person has a relatively small number of contacts.


Ratio of outgoing to incoming messages per TN

1:1 with some latitude in either direction

Human communications are conversational. An incoming message typically generates a response from the recipient.


25 Repetitive Messages

Typically person behavior is not to send the same or essentially repetitive messages.

Application-to-Person (A2P)

Any type of traffic that does not fall under the P2P definition is considered A2P. Essentially traffic that is not consistent with typical human characteristics.

Messaging Classification



Opt-In and Opt-Out

Typically not required as consumer-to -consumer

Express consentOpt-out (e.g., STOP keyword)

Traffic Volume

Consistent with typical human operation

As contractually agreed

Program Review Process

Not required

May be required

Recommended Usage

Consumers texting one or more consumers.

Enterprises texting multiple consumers simultaneously

Call Center

Alerts and notifications

Machine to Machine

Typical Scenarios

Traditional individual conversational Texting.

Group messaging with appropriate opt-out capabilities.

Call Center scenarios; session typically initiated by consumer. Permission for session is assumed.

Typical bulk messaging campaigns, marketing, business outreach, two factor authentication.

Recipients should be notified periodically how to opt out.

Service providers enforce the STOP layer.

These Principles and Best Practices do not provide legal advice or guidance, the messaging ecosystem should operate consistent with relevant laws and regulations, such as the Telephone Consumer Protection Act (TCPA) and associated FCC.

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