When you first sign up to an SMS API provider so you can send out mass text message campaigns, you'll need to create a Sender ID. This is a unique identifier that your subscribers will see when they receive your texts. You can get one in the form of a short code, toll-free code, or 10-digit long code (10DLC). This post focuses primarily on the last one. We'll talk about what is a 10DLC phone number, how it compares to other Sender IDs, its key benefits, and how to set one up with Messente.

Related: What is a Sender ID?

What is 10DLC in A2P messaging?

10DLC is a system used in the U.S. for Application to Person (A2P) text messaging. It's an abbreviation for '10-digit long code', which is a special ten-digit phone number. A2P messaging is the technology that enables businesses or brands to send out text messages en masse to hundreds, thousands, and even millions of subscribers simultaneously. 10DLC phone numbers enable that by supporting a high volume of text messages.

Regular phone numbers (also 10 digits in the U.S.) were originally built by the U.S. carrier community for person-to-person (P2P) text messaging. As the name suggests, this is where a person texts another person from their mobile device. Short codes, which are five or six-digit numbers, were introduced more than a decade ago for A2P messaging.

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That said, up until a couple of years ago, it was also possible for businesses to leverage P2P messaging to send a few hundred messages. However, this resulted in A2P traffic being mixed with P2P traffic, making it difficult for carrier networks to protect consumers from spam.

Around 2021-2022, major U.S. carrier networks like Verizon, T-mobile, and AT&T announced their migration to 10DLC for A2P messaging. The programme gives carriers more power in identifying reputable senders and, of course, those sending unsolicited texts.

Spam texts are rife in the U.S. An average of 14.7 spam text messages were received per person per month in 2020, and 16.9 in 2021. The number has continued to rise. According to the latest figures from Robokiller, an expert in spam detection, this average has risen to 19 spam texts per person in January 2024.

For business text messaging in the U.S., 10DLC numbers are the new SMS industry standard, leading to more trusted messaging in general, with strong 10DLC compliance requirements in place.

There are certain costs involved with A2P 10DLC registration, but it also has more flexibility when it comes to SMS prices, so it is quite efficient for companies sending over 10k messages per month. They come with a local area code of your choice, which is most useful for companies targeting local areas.

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A2P 10DLC compared to other Sender IDs

Let's explore all the different types of SMS codes for business messaging and see how 10DLC stacks up against them.

Dedicated short codes

These five- or six-digit numbers can be used to send millions of text messages per day at a very speedy rate. Around 500 messages can be sent per second using a short code number. However, short codes can be costly, involving a leasing cost and a volume cost. Plus, short codes often involve a lengthy setup and approval process, which can typically take between eight and twelve weeks.

That said, short codes are ideal if you need to send high volumes of text messages from a memorable number that your audience will recognise as part of your brand identity. And, once set up, the number won't go through carrier filtering, which is great news for those with concerns about deliverability.

Long codes

Long codes are standard phone numbers. Although these aren't designed (or approved) for A2P messaging, if you need to text your customers individually, e.g., for customer service texts, a long code could be your best option. But long codes only transmit approximately one message per second, so they can't really be used to message large groups of people.

Toll-free numbers

A toll-free number is a long code number that begins with a three-digit code, e.g., '800' or the '888' nationwide "area code".

Toll-free codes are best used when you need to message customers back and forth or switch from text to voice calls like you might for customer service or sales support.

Toll-free numbers can also be used to send one-way alerts but aren't suitable for high-volume SMS marketing campaigns. They're cheaper to register (€5 per month) but not as flexible in SMS pricing, so it is a simple and cheap solution for businesses sending less than 5000 messages a month. They are a relatively affordable option, and you can sometimes use your existing phone number, too. Set up can take a while, though (around two weeks).


With 10DLC, you get the ability to send mass marketing messages (and transactional texts) without the expense associated with short codes. The messaging rate (aka message throughput) for 10DLC is currently around five to fifteen messages a second (much higher than a regular long code).

That said, if you need to send higher SMS message volumes, you'll probably be better off using a short code. A 10DLC number is ideal for sending messages such as two-factor authentication alerts, appointment or payment reminders, and order confirmations.

Deliverability is generally better with 10DLC numbers than standard long codes because, like with short codes, you'll have to go through an approval process with carriers to obtain a 10DLC number.

The benefits of 10DLC numbers

We've already talked about some of the key ways your business could benefit from signing up for a 10DLC number. Let's do a quick summary, along with some bonus points.

  • You can achieve a great volume-price balance if you text from a 10DLC number, somewhere between what you get with toll-free and short code numbers. The best of both worlds for your bulk messaging needs!

  • You will be able to match your costs to your texting capacity each month. 10DLC numbers offer flexibility and scalability.

  • You can get a pre-approved number from the carrier, which means your text messages to your customers will be less likely to get flagged as spam (as long as you follow the rules and laws), and you will stay a green flag. You'll also be able to easily catch up on and follow the 10DLC rules for the carrier you're associated with.

  • You will get a high deliverability rate, making sure that the messages that you put so much thought and effort into actually reach your customers instead of getting lost or ignored.

  • For a certain campaign, you can simply convert your landline number to a 10DLC SMS number. This way, you won't have to introduce a completely new, different number to your existing customer base, who might already be familiar with your old local phone number. Plus, you'd save on the cost of managing two different numbers for calls and texts, too.

  • On top of allowing phone calls, 10DLC numbers also support two-way messaging, making them ideal for diverse customer communications.

  • Compared to the two weeks that it can take to set up a toll-free number, 10DLC numbers take only 4-5 days, so you can get started much faster with the latter.

Registration process: How to set up a 10DLC with Messente

Any businesses or brands wanting to adopt 10DLC messaging must register with U.S. carriers to get approval. An A2P 10DLC number can only be used by a single sender for a single-use campaign (10DLC campaigns are use cases, which can be standard or special). This is so the carriers can identify the type of text being sent from each number by each business or brand.

The vetting process involves a bit of data gathering on your part. You need to submit information such as your business name and other company details, contact details, URLs, the use case for the text messages, campaign descriptions, how the customers will opt-in to receive the mentioned SMS contents (more on this later), and more.

You must undergo the A2P 10DLC registration process whether you're sending marketing or transactional texts, and irrespective of how many texts you intend to send. All your A2P 10DLC SMS campaigns need to be registered with The Campaign Registry (TCR).

Here at Messente, we can register your business and use cases with the U.S. mobile network operators to generate your 10DLC Sender ID, ready for sending out text campaigns. Reach out to us, and we will set the wheels in motion.

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Opt-in and opt-out

Data protection laws require that the recipients give their explicit consent before receiving any SMS from your company's number. It is best to make very clear on your website/app, what happens to their phone number after entering. Here are some examples of what you can add to your check-out page:

Opt-in examples on a check-out page

Content restrictions

The SMS industry in the US is highly regulated by the FCC's TCPA (Telephone Consumer Protection Act) and CTIA (an association representing the U.S. wireless communications industry). They control what content can be sent and on what conditions. When the guidelines are not followed, messages will get blocked by the operators. For the SMS content that you will be sending through your 10DLC number, many rules are similar across countries - general restrictions apply, which are mentioned in our Terms and Conditions.

You're not allowed to send political, religious, unsolicited promotion, gambling, high-risk financial service, or illegal substance content through 10DLC numbers (or any other type of Sender ID). Some sensitive contents, such as tobacco, alcohol, CBD, and gambling, may be allowed, given you follow the proper procedures and meet certain conditions.

10DLC demystified

To sum up, a 10DLC (10-digit long code) is a U.S.-specific, carrier-approved phone number (Sender ID) generated for business texting and, more specifically, for A2P messaging. You might want to use a 10DLC if you don't need to send massive volumes of texts simultaneously and don't want to pay the costs associated with setting up dedicated short codes for SMS messages.

If you're actively looking to launch an SMS campaign with considerable message volume, using a 10DLC to send messages is a no-brainer. This is often far more effective than using a short code that comes with sizable costs.

Local long codes (using your local area code) are approved by mobile carriers and prevent you from sending spam-like text messages, potentially improving customer engagement, satisfaction, and trust scores.

10DLC is a low-cost option for sending out a range of transactional and promotional texts, like 2FA pin codes, appointment reminders, order and shipping confirmations, flash sale notifications, and a lot more.

Have questions not answered here? We're happy to help - get in touch.