UNITED STATES (US)

Country Summary

Country name	United States
ISO code	US
Region	North America
Mobile country code	310, 311,
Dialing code	+1
Major carriers	AT&T, Verizon, T-Mobile, Sprint

Guidelines

Two-way SMS supported	Yes
Message length	1600 characters. Sprint does not support concatenation and messages will be delivered as multiple segments.
Twilio MMS support	Supported
Sending SMS to landline numbers	Twilio 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. More detailed guidance can be found here. 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: Get opt-in consent from each end user before sending any communication to them, particular for marketing or other non-essential communications. Only communicate during an end user's daytime hours unless it is urgent. SMS campaigns should support HELP/STOP messages, and similar messages, in the end user's local language. Do not contact end users on do-not-call or do-not-disturb registries. Note: The euro symbol (€) is not supported; avoid using this character in message submission toward the United States.

Phone Numbers & Sender ID

	Alphanumeric		Long Code		Short Code
	Pre-registration	Dynamic	Domestic	International
Operator network capability	Not Supported	Not Supported	Supported	Not Supported	Supported
Twilio supported	Not Supported	Not Supported	Supported	Not Supported	Supported
Sender ID preserved	No	No	Yes	No	Yes
Provisioning time	---	---	None	---	8-12 weeks
UCS-2 support	---	---	---	---	---
Use case restrictions	---	---	Application-to-person (A2P) messages sent via long codes may be subject to carrier filtering. Learn more at https://support.twilio.com	---	A subset of short code use cases are prohibited by carriers. Learn more at https://support.twilio.com
Best practices	---	---	Refer to our FAQ for long code best practices.	---	Refer to our FAQ for short code best practices.

	Alphanumeric - Pre-registration
Operator network capability	Not Supported
Twilio supported	Not Supported
Sender ID preserved	No
Provisioning time	---
UCS-2 support	---
Use case restrictions	---
Best practices	---

	Alphanumeric - Dynamic
Operator network capability	Not Supported
Twilio supported	Not Supported
Sender ID preserved	No
Provisioning time	---
UCS-2 support	---
Use case restrictions	---
Best practices	---

	Long Code - Domestic
Operator network capability	Supported
Twilio supported	Supported
Sender ID preserved	Yes
Provisioning time	None
UCS-2 support	---
Use case restrictions	Application-to-person (A2P) messages sent via long codes may be subject to carrier filtering. Learn more at https://support.twilio.com
Best practices	Refer to our FAQ for long code best practices.

	Long Code - International
Operator network capability	Not Supported
Twilio supported	Not Supported
Sender ID preserved	No
Provisioning time	---
UCS-2 support	---
Use case restrictions	---
Best practices	---

	Short Code
Operator network capability	Supported
Twilio supported	Supported
Sender ID preserved	Yes
Provisioning time	8-12 weeks
UCS-2 support	---
Use case restrictions	A subset of short code use cases are prohibited by carriers. Learn more at https://support.twilio.com
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.