‹   Back

United States SMS messaging regulations and restrictions

All SMS messaging in The United States of America is governed by the CTIA – The Wireless Association. Strict rules are in place to regulate USA messaging, and it’s important to work closely with your sales advisor to ensure your program is compliant with the latest regulations at all times.

Note that Federal Communications Commission (FCC) bans SMS messages sent to a mobile phone using an auto-dialer, unless prior consent has been received by the user or the message is sent for emergency reasons. The ban applies to all numbers, including those not specified on the Do Not Call list.

Short codes are ideal for marketing messages, any form of bulk messaging, or messages containing URLs. The regulations for US short code will be provided to you once your application is approved. You can also view the CTIA Short Code Monitoring Handbook. Long numbers are typically used for sending person-to-person communication like appointment reminders, alerts, and announcements. That means you may use it to send messages to customers, employees and other individuals with an interest in your business. The restrictions below only apply to long numbers.

Our expert advisors are up to date with the latest US messaging regulationsand can guide you as you set up and maintain your program. Email expertadvisors@clickatell.com to get started.

Restriction* Description
Sender ID Because all messages must be sent via long number or short code, a sender cannot have an alphanumeric or other numeric code for sending message. Your from address must contain your pre-approved US sender number typed in international format.
Opt in Recipients need to consent to receiving marketing communication in writing (i.e. email or other) before you start sending marketing messages to them.
Opt out
  • Each marketing SMS must contain an opt-out option.
  • Two-way numbers are mandatory to ensure that people can unsubscribe.
Message format
  • Text messages may be a standard length of 160 characters (136 characters in Canada).
  • Unicode is supported and limited to 70 characters per SMS.
  • Concatenation and binary is not supported.
  • The symbol for Euro (€) is not supported.
Content of message
  • The content of all marketing messages must be appropriate for the intended audience, particularly when it comes to marketing to minors.
  • Do not disseminate inflammatory content, or content that may cause offence or harm to recipients (deliberately or otherwise).
  • Using keywords or URLs repetitively in the body of long numbers is likely to cause your messages to be blocked by networks.
Message frequency
  • If you send more than one SMS per second, your messages will be rejected by the carriers. Should you require a higher sending frequency, consider purchasing additional numbers.
  • Message volumes for each long number are limited to 5000 per day. Exceeding this limit could result in your number being blocked.
  • On a two-way number, carriers expect to see two-way SMS traffic.

*Table applies to long numbers only

Other resources

Ask the community

Visit Stack Overflow to join our community of developers and find the answer you need.
Visit Stack Overflow

Contact support

Contact our support team and one of our agents will be in touch with you to answer any questions you have.
Contact us

SMS Platform

Clickatell SMS Platform is a bulk SMS system that enables you to send messages securely, reliably and instantly, sparking a dynamic dialogue between business and customer.

Find out more