How to Choose a Phone Number for SMS Marketing Campaigns

Long codes, toll-free numbers, short codes — businesses in the US have a lot of options for communicating with their customers via SMS. How did we get so many, and which option is best for what use case?

A brief history of phone numbers

Few of us are old enough to remember when a phone number was just a phone number — seven digits and an area code. Today we call these long codes. When you dialed a number, the call went over copper wires and through switching stations, and if you had to call long distance, the phone company (there was only one) charged you a lot of money per minute. In the US, AT&T had a monopoly on telephone service, and everything was simple.

In 1967 AT&T began offering a new option — Wide Area Telephone Service (WATS). If a business bought a number with the special area code 800, people could call in at no cost to themselves — the business paid instead. It was the beginning of what we now call toll-free numbers, and they grew so popular that now several area codes are required to meet the demand for them.

In 1984 an antitrust case broke up AT&T into several competitive companies. Around the same time mobile phone service, using radio waves instead of wired connections, began to emerge. In the late ‘90s, mobile phones gained alphanumeric keyboards, and suddenly texting took off. Now people could use phones for both voice calls and messaging.

Texting was such a useful tool for marketing that in 2003 the Mobile Data Association introduced short code phone numbers: easy-to-remember five- or six-digit numbers designed to “allow customers to initiate immediate contact with a specific promotion.”

The latest phone number type to emerge is 10DLC (10 digit long code), which was codified in 2017. Weren’t long codes always 10 digits? Yes, and maybe the CTIA could have chosen a better name, but here we are. Businesses have to register their numbers and their marketing campaigns to use 10DLC numbers. In exchange, they get high messaging throughput and improved deliverability. Why do we need a separate category of long codes?

P2P vs. A2P

When texting first emerged, all messages were person-to-person (P2P). People sent only a small volume of messages within a given time and used texting for conversations.

But text messaging was such a good communication channel that businesses quickly adopted and automated it. Application-to-person (A2P) messages can send large volumes of messages within a short time. It made sense for carriers to recategorize A2P messaging as a separate service and charge different (higher) rates for it.

What kinds of numbers are available?

Today, businesses have four options for text messaging: long codes, 10DLC, toll-free, and short codes. For each, you pay two kinds of fees: phone number rental (a monthly cost) and pay-as-you-go pricing for each message that you send. Let’s consider the best use cases for each kind of phone number.

When should you use a long code?

Since the emergence of 10DLC, businesses have fewer reasons to use good old long code numbers for text messaging. Long codes are fine for sales people answering questions initiated by customers — P2P messaging, in other words. But organizations should no longer use unregistered long codes for marketing messaging.

When should you use 10DLC?

10DLC has taken over from long codes as the preferred number type for marketing messaging. 10DLC allows you to send a higher volume of messages within a given time; throughput limits vary by carrier, but are in the neighborhood of tens of messages per second. Per-message costs for 10DLC messaging are reasonable.

To take advantage of 10DLC, you have to register your long code numbers with an organization called The Campaign Registry, which you can often do from your provider’s dashboard. Once you’re registered, the messages you send won’t be considered spam, so 10DLC promotes higher deliverability than long codes.

When should you use a toll-free number?

You can use a toll-free number for A2P texting, but in most cases 10DLC is a better choice because it’s less expensive and offers higher messaging throughput. If your business is known by its toll-free number, that’s a different story. (Looking at you, 1-800-ASK-GARY.)

When should you use a short code?

The use of short coeds is changing. In the past, businesses could share short codes between multiple brands. That was tricky, because consumers could be confused when brands shared a short code. Also, if a brand used a short code in a way that violated their carrier’s compliance regulations, the carrier could shut down the short code, affecting all the brands that shared it.

Today, if you want to use short codes for messaging, you need a dedicated short code for each brand. It can take eight to 12 weeks to provision a new short code — longer than the time for other phone number options.

A key benefit of short codes is high messaging throughput — up to hundreds of messages per second — so you can send more in a shorter space of time.

Vanity short codes — ones whose numbers spell out a company name or other keyword, such as 75486 for Plivo or 827438 for Target — have the advantage of being easy to remember. Random short codes are also available, generally at a lower cost.

By the way, short codes are the only one of these number types that can’t be used for voice calling.

The bottom line

Nowadays, if you’re sending out marketing messages, plan to register one or more 10DLC numbers for your SMS messaging campaigns. If you need high throughput for your messaging, register short codes. To take best advantage of all of your phone numbers, use them in concert with a cloud communications platform to send out your campaigns.