Sending SMS in the US

Navigate the regional rules of using SMS as a business in the United States.

Gareth Burroughes avatar
Written by Gareth Burroughes
Updated over a week ago

Did you know that in the US, there are 5.5 billion text messages sent every day (CTIA Wireless Report), equating to 63,000 every second?

Not only that, but according to U.S. Pew Research Center, as of February 2019, 96% of adults in the US own a cell phone, and every single one of those phones is SMS-enabled. If you’re starting to think you should be making more of SMS as a business, you’re not alone. The US SMS marketing market size was valued at USD 3.5 billion in 2018 and is expected to register a compound annual growth rate (CAGR) of 20.3% between 2019 and 2025. 76% of consumers are reported to have received some kind of text message from a business, and it’s not just direct to consumer models who are using the channel; the use of SMS marketing grew 197% as a strategy in B2B efforts from 2015 to 2017 (Salesforce), setting a clear trend for the future.

It’s clear to see why businesses are turning more and more to texting. SMS is a valuable channel for both reach, and ROI. But complexities of sending SMS as a business in the USA can often put brands off sending at all. In this guide, we walk you through some of the historical reasons this region is distinct from the rest of the world, as well as explaining the differences between your options for sending.


Gathering opt-ins

Unlike other parts of the world, mobile numbers in the US Region have area codes instead of a mobile-only prefix, so it is not possible to know by looking at a number if it is a mobile or not. This means that, traditionally, mobile users paid to receive calls and SMS, since it was not fair to burden the sender with any extra costs when they did not know they were contacting a mobile. For this reason, it has been more important to prove someone has opted in than in the rest of the world. Today, call and SMS bundling, and the introduction of toll-free numbers, have made this less of a concern. Nonetheless, it has left a lasting, regulatory effect on how businesses must use SMS. In the US, text messages fall under the Telephone Consumer Protection Act (TCPA), which is the main anti-abuse/ telemarketing law. This means that gathering compliant opt-ins is a crucial first step for any SMS marketing in the region.

There are many ways to gather phone numbers which have been opted in to receive marketing from your business. Asking for phone numbers at the point of customer sign up is a great way to build a data base. You may also want to leverage our pages and forms functionality to create on-brand data capture with ease. Just remember to check with your legal team or key regulatory bodies (see below) that you are being compliant, and to specify you are asking for a ‘cell’ or ‘mobile’ number. Since there is no way to tell if the number is cellular by its formatting, you must rely on your form capture to clearly specify what you are asking for. Telling customers that you are asking for this data in order to send SMS is not only required, but can also help increase the likelihood of capturing a mobile number instead of a landline.

Key regulatory bodies


Mobile Marketing Association – the US Centric, global trade body that with carriers (see CTIA) sets regulations for A2P messaging in USA.


Cellular Telecoms Industry Association ‘The Wireless Association’ The US Networks Trade association.


Federal Communications Commission Regulations.


Telecommunications Protection Act (1991) The act under which the FCC is able to prosecute.


Canadian Wireless Telecoms Association – For information on short code messaging in Canada. From here, you can also download the ‘Canadian Common Short Code application Guidelines’ which are the MMA Best practice guide equivalent for Canada.

Numbers that businesses in the US can send from

Unlike some other regions, options for sending in the US are limited, which can make choosing much easier!

In the US, marketers cannot or should not send from:

  • Alphanumeric names (such as your brand name)

  • Long codes

  • Shared short codes

There has been a shift within the US text messaging and marketing industry on what numbers should be used for application-to-person messaging (A2P). For example, long code messages are capped at 250 SMS per day and not intended for marketing, effectively banning their use for A2P messaging.

And so the US introduced a new type of messaging called 10DLC (a 10 digit long code) in May 2021. Your options for sending marketing in the US via SMS therefore are:

Toll-free, dedicated short codes, and 10DLC

It should be noted that toll-free codes have until now been accepted by networks as better than long codes since the message recipient does not pay to receive messages. For the present they will continue to be accepted, but there is a possibility in future that networks will start to treat them less favourably, with the intention of encouraging businesses increasingly to move to 10DLC. This guide deep dives into each available option and includes comparisons between each so you can decide which sending method is best for your business.

Toll-free number

Toll-free numbers are a great way to send simple low-cost marketing messages in the USA. You can send from them as the sender ID, your customers can reply directly back to them and marketing is accepted.

They can be set up instantly in-app. Before use the number will need to be verified by the carriers (networks). In order to verify we will ask for the information below. Once received the application takes 1-2 weeks.

  • Full details on how opt-in is collected including URL

  • Full contact details

  • Sample content of 2-3 messages

  • Whether the campaign includes Canadian traffic

  • A campaign description

  • Estimated monthly message volumes

  • The business type category

If someone with a US mobile is roaming outside USA, they should still be able to receive and reply to any toll-free messages sent to them (this is network dependent and not guaranteed). However, it is not reliable to send to non-US or Caribbean mobiles using toll-free, as it could result in being charged for non-delivered messages. Make sure to use another option for sending outside of the US. Likewise, non-US mobile are unable to text a toll-free number so this method cannot be used as an international single reply number for multiple countries.

Transferring toll-free numbers

We can almost always transfer toll-free numbers from other provider at no additional cost beyond standard setup. You may have a number being used for SMS only and want to transfer the whole number. This requires a completed Letter of Authorisation (LOA) and usually takes around 2 weeks. The voice element of voice-enabled numbers can also be transferred.


It is important to make it easy for people to opt out. We recommend that at least one message monthly includes “...Reply STOP to Cancel” or similar. While not mandatory for toll-free, other areas of best practice can also be taken from the rules for dedicated short codes. Fortunately for Dotdigital users, you can set-up automatic rules to make compliance that bit easier.


10 digit long codes (10DLCs) are now live on all main and the majority of smaller networks.

10DLCs are now fully live on all main networks (Verizon, AT&T, T-Mobile, an Sprint). Many other smaller networks are also live which means that effectively all mobile users in the US can now be reached with a 10DLC number.

Dotdigital is registered with The Campaign Registry and can help you set up your campaign. Speak to your Customer Success Manager to find out more about associated costs.


The same information is required to apply for a 10DLC as a short code and is explained here. 10DLC setup can be completed in as little as a day if the correct information is available. Throughput for 10DLCs is per number and is determined as part of the application through a vetting process that takes into account the use case as well as multiple brand trust factors. Each network allocates throughput according to their own process and trust score. Dotdigital conducts basic 3rd party vetting, whereby simple steps are taken to maximize the trust score as part of every application. If an organization is not happy with the trust score (and therefore the throughput allocated), a chargeable review can be requested.

Dedicated short code

Dedicated short codes have higher associated costs than a toll-free and 10DLCs, and set-up takes four to six weeks after the application has been finalized. B

oth 10DLCs and dedicated short codes involves the completion of an application form which we can assist you with. Once ready, this is submitted to the US networks for approval of the use case.

The application is extensive as it requires message flows which must be approved by networks to comply with important ongoing regulation such as opt-ins. It also requires a mock-up of planned web pages. These pages will also need to be live, at least on a temporary URL, for the code to be approved to go live. You can find out more information about these mock- ups on page 12 - “Example short code/10DLC message flows”.

Toll-free vs dedicated short code

Both toll-free and dedicated short codes have the following in common:

  • Marketing use is permitted (provided they abide by industry guidelines and regulations)

  • Both are offered as a dedicated number, toll-free is a long number and the short code is... you guessed it!

  • No daily send limit applies

  • Delivery receipts are available

  • Both permit the inclusion of URLs in the message BUT toll-free does not support anonymous URLs like Shortened Dotdigital URL’s are always supported


So what are the differences?

  • A dedicated short code will be more costly than toll-free – a six-month minimum term also applies to dedicated short codes whilst for toll-free a three- month minimum term applies

  • Throughput (messages per second) is higher on dedicated short codes than toll-free.

  • The set-up processes also differ. At 1 to 3 days (or for some Dotdigital users instantly in-app) plus 1 to 2 weeks for verification, toll-free is far easier to set up. A dedicated short code set up can take 4 to 6 weeks and requires the submission of a detailed application with supporting message flow so that their use case can be approved.

  • Finally, the rules and regulations they follow are technically not the same. Dedicated short codes are governed by CTIA and TCPA regulations. Toll-free numbers work along guidelines of good practice, not regulations. At Dotdigital, we recommended you still follow dedicated short code guidelines to improve delivery, keep your recipients happy and opt-in and engagement rates high.

Toll-free vs. 10DLC

Both toll-free and 10DLC have the following in common:

  • Marketing use is permitted (provided they abide by industry guidelines and regulations)

  • Setup time is 1-2 weeks at most, and typically less.

  • Both support URl’s but anonymous type URL’s (see page 9) are advised against. Shortened Dotdigital URL’s are always supported.

  • You can expect a similar throughput across toll-free and 10DLC numbers, however 10DLC. throughput can vary slightly based on the use case.

  • Both can be voice-enabled if required.

  • A single number cannot be shared between organizations.

So what are the differences?

  • 10DLC does not provide delivery receipts, toll-free does

  • A monthly pass-through fee per campaign applies for 10DLC. Messages rates are cheaper however so at high message volumes 10DLC may still be the most cost-effective option available

  • 10DLC is governed by CTIA and TCPA regulations. Toll-free SMS works to guidelines of good practice however we recommend a similar level of care is taken for recipients

  • 10DLC appears as a regular geographic US number whereas toll-free is an 8xxx number

  • There is no daily send limit with toll-free. With 10DLC this is more variable; a good use case could allow over 100,000 a day, whilst a poor use case on 10DLC could incur a daily send limit of 30,000 or less

10DLC vs. dedicated short code

Both 10DLC and dedicated short codes have the following in common:

  • Marketing use is permitted (provided they abide by industry guidelines and regulations).

  • The same guidelines, regulations and sanctions apply to both, from the CTIA and main network codes of conduct.

  • There are no practical cases where either will allow one number to be shared between organisations

  • US dedicated short codes can and 10DLC will, reach Canada from the same code.

So what are the differences?

  • Set-up time can be minutes with 10DLC, but will continue to be 4-6 weeks for short codes.

  • 10DLC does not and will not provide delivery receipts. Short codes do.

  • 10DLCs are more cost-effective than short codes making it feasible to have a dedicated 10DLC per case where there was previously a shared code.

  • Throughput (messages per second) is higher on short codes than 10DLC.

  • 10DLC appear as regular US mobile numbers and have the option of being voice-enabled.

Quick tip

A guideline on good SMS practice for can be found here. Most guidelines are straight forward, including the recommendation to include “HELP” as a reply option to request info on the service, but what some networks consider red flags may surprise you.

For example, redirects should be kept to a minimum. Using a shortened link (which redirects to the full URL) is fine, but some brands have been known to redirect 4-5 times to drive their clicks up. This is not advisable, and messages have been blocked as a result.

Example short code/10DLC message flows

For short codes and 10DLCs only

Message flows are not required if sending from a toll-free number

We have compiled a few examples of dedicated short code and 10DLC message flows. This list is not expansive but intended to demonstrate the level of requirement for dedicated short code regulations in the US.


If you want to send recurring SMS, the end-customer must receive a message as below immediately after the opt-in. In Dotdigital you can set-up an appropriate auto- response to each prompt. Note that in the event you want to send abandoned cart messages, the end user must complete a full double opt-in. This means that the end user must reply with for example ‘Yes’ after the confirmation message has been received. Only then can abandoned cart messages be sent.


This screenshot shows the response a client needs to get if they text HELP:


Below is an example of the requirements for a single-item call-to-action keyword opt-in (on a website or possibly a poster).


Your account manager and our operations team will go through the full list of message flows that are required and work with you on these before submitting to networks for approval.

Further information

Quiet Hours

The quiet hours for SMS marketing are between 9pm and 8am. Remember, the USA has up to 3 hours time zone difference within it, so if you do not know the location of your customers, marketing should be complete by 6pm EST and not start before 11am EST.


Your privacy policy page can largely stay the same but you must ensure that mobile phone numbers and other customer details collected for mobile campaigns are explicitly mentioned as covered within the policy.

Note that when a consumer opts in to a specific short code they do so for a particular ‘campaign’ only – this may be for example to receive marketing messages from a brand. This opt-in will only ever apply to that brand and can not be used for any 3rd parties. A campaign from a brand that in effect is an agency for other brands will not be accepted, since it would involve passing information on to a 3rd party.

As part of important ongoing regulations, short code programs should promote customer care contact details and opt-out instructions at regular intervals, at least monthly, either as part of content or in separate service messages.

Transferring dedicated short codes

An existing dedicated short code number can be transferred to Dotdigital with the same number and same service. In this case, there is no need for end users to opt in again or even get a service message. We can also transfer an existing dedicated short code service to a new short code number with Dotdigital. To change your number the following three steps must be taken in order (please ask for details as required):

(a) Send a specific final message from the old number that includes the new number

(b) Within 24 hours send an equivalent message from the new number

(c) Immediately stop sending messages from the old number

Transferring 10DLC and Toll-free codes

It is normally quite simple to transfer either of these code types to Dotdigital. Ask for details of the information that is needed to do this. Once we have the information, the change takes a few days.

Carrier-specific regulations

Separate to this general short code guide and the industry guides, two of the three main carriers (who share >98% US penetration) have published their own short code guides which we can supply on request. These are very useful if certain use cases are desired and they detail how to make a successful application for them.

Normally, prohibited cases include any that fall under SHAFT-C (sex, hate, alcohol, firearms, tobacco, cannabis).

Special use cases that are not permitted or that require extra authorisation (from T-Mobile or AT&T) are listed below:

  • Any affiliate marketing seeking to generate opt-in lists

  • SMS for ‘Work from home and make $$$’ or investment schemes

  • Loan or debt relief

  • Lead generation campaigns that indicate the sharing of collected information with third parties

  • Gambling via SMS

  • ‘Free-to-end-user’ programmes

  • Sweepstakes and contests

  • Some limited adult and controlled substance content

  • Charitable donations

  • Emergency notifications

  • M2M messages

  • Abandoned cart reminders (see below)

Please contact us with the particular use case if you would like to do anything that may be connected to any of the above, in order to get a view on how likely it would be to get approved.

Abandoned cart reminders

We know that abandoned cart reminders are highly attractive messages with the potential to recover revenue. There are some restrictions to be aware of to ensure you are compliantly sending these messages:

  • The call-to-action must clearly state the campaign includes an abandoned cart reminder.

  • The recipient must double opt-in to receive these - first on the website and then via a reply to an SMS they will receive.

  • A double opt-in is required meaning that if a customer initially opts in on your website, they must subsequently also opt in via the SMS.

  • Each opt-in must clearly state the program will include abandoned cart reminders.

  • No more than one reminder text per abandoned cart can be sent, and this must be sent within 48 hours.

  • The SMS must not result in the e-commerce site completing the sale or collecting payment.

  • Further privacy and other details are available from Dotdigital on request.

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