UNITED STATES (US)

Country Summary

Country nameUnited States
ISO codeUS
RegionNorth America
Mobile country code310, 311,
Dialing code+1
Major carriersAT&T, Verizon, T-Mobile, Sprint

Guidelines

Two-way SMS supported Yes
Message length1600 characters. Sprint does not support concatenation and messages will be delivered as multiple segments.
Twilio MMS supportSupported
Sending SMS to landline numbersTwilio will not check whether the number is a landline and will attempt to send it to our carrier for delivery. Some carriers will convert the SMS into text-to-speech messages via voice calls.
Compliance considerations

Twilio recommends sending application-to-person (A2P) traffic over short codes for optimal delivery results. Messages sent over over long codes are subject to carrier filtering because A2P traffic is not permitted over US long codes. Twilio does not definitively know how many messages can be sent from a long code before a user can expect to hit a filter. However, we recommend following the guidelines mentioned in Messaging Principals and Basic Practices published by CTIA in Jan. 2017, where CTIA suggests that application-to-peer (A2P) messaging that's "consistent with typical human operation" should be expected to be deliverable across the messaging ecosystem. Some key attributes of typical human operation include: - Throughput: 15-60 messages per minute - Unique Recipients: 200 unique recipients per day The euro symbol (€) is not supported; avoid using this character in message submission toward the United States.

Twilio strongly encourages customers to review proposed use cases with qualified legal counsel to make sure that they comply with all applicable laws. The following are some general best practices:

  1. Get opt-in consent from each end user before sending any communication to them, particular for marketing or other non-essential communications.
  2. Only communicate during an end user's daytime hours unless it is urgent.
  3. SMS campaigns should support HELP/STOP messages, and similar messages, in the end user's local language.
  4. Do not contact end users on do-not-call or do-not-disturb registries.

Phone Numbers & Sender ID

PreregisteredAlphanumericLong CodeShort Code
Operator network capability --- Not SupportedSupportedSupported
Twilio supported --- --- SupportedSupported
Sender ID preserved --- --- YesYes
Provisioning time----None8-12 weeks
UCS-2 support --------
Use case restrictions ----Application-to-person (A2P) messages sent via long codes may be subject to carrier filtering. Learn more: https://support.twilio.com/hc/en-us/articles/223181848-How-Does-Carrier-Filtering-Work-A subset of short code use cases are prohibited by carriers. Learn more: https://support.twilio.com/hc/en-us/search#stq=short+codes+short+code+campaigns+prohibited+by+carriers&stp=1
Best practices ----As per the CTIA Messaging principles and Best Practices, we recommend sending to no more than 200 unique recipients per day from a Twilio long code at a rate of of no more than 15-60 messages per minute to avoid possible carrier end filtering.Refer to our FAQ for short code best practices.
Preregistered
Operator network capability ---
Twilio supported ---
Sender ID preserved ---
Provisioning time--
UCS-2 support --
Use case restrictions --
Best practices --
Alphanumeric
Operator network capabilityNot Supported
Twilio supported ---
Sender ID preserved ---
Provisioning time--
UCS-2 support --
Use case restrictions --
Best practices --
Long Code
Operator network capabilitySupported
Twilio supportedSupported
Sender ID preservedYes
Provisioning timeNone
UCS-2 support --
Use case restrictions Application-to-person (A2P) messages sent via long codes may be subject to carrier filtering. Learn more: https://support.twilio.com/hc/en-us/articles/223181848-How-Does-Carrier-Filtering-Work-
Best practices As per the CTIA Messaging principles and Best Practices, we recommend sending to no more than 200 unique recipients per day from a Twilio long code at a rate of of no more than 15-60 messages per minute to avoid possible carrier end filtering.
Short Code
Operator network capabilitySupported
Twilio supportedSupported
Sender ID preservedYes
Provisioning time8-12 weeks
UCS-2 support --
Use case restrictions A subset of short code use cases are prohibited by carriers. Learn more: https://support.twilio.com/hc/en-us/search#stq=short+codes+short+code+campaigns+prohibited+by+carriers&stp=1
Best practices Refer to our FAQ for short code best practices.

For the benefit of all our customers, these guidelines are provided to help you comply with applicable requirements and to help ensure Twilio's platform remains compliant with global telecommunications ecosystem requirements. These guidelines represent our current understanding of common compliance requirements generally applicable to Twilio and its customers, and do not constitute legal advice. By posting these guidelines, Twilio makes no assurances regarding the legal compliance of your application built using our APIs. You are expected to understand and abide by all compliance obligations applicable to your specific application. You should check these pages regularly for updates as telecommunications ecosystem requirements continue to evolve and change, and the information below may be updated or changed without notice.