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10DLC and Short Code SMS : Controlling the megaphone

Of all my inboxes, there’s one I consider, well…. mine.

I have all the normal channels; SMS, email, MS-Teams messaging and Social Media. But among all of these, there’s one that I think of as uniquely mine – that’s my SMS/MMS text messaging inbox. Maybe it’s because my text inbox is inextricably connected to my cellphone number, or maybe because it hosts messages from folks that are close to me. Either way, it is the one single place that I will not tolerate spam. I send STOP replies, I am careful with what services I expose to it, and I expect it to only whistle when I have received a message I want. Apparently, telecom companies feel the same way about it. For some time (in fits and starts) there has been an effort by the large telecoms to better control unwanted SMS messages, blasted at their subscribers.

A2P (Application to Person) type messaging has been available Through several different channels for some time. Let’s review these channels:

Long Codes

Until very recently, anyone could establish a 10 digit standard “Long Code” telephone number (ex 212-222-1357) and write some code to blast out messages. Long codes could be obtained with a low barrier to entry (I.E. no official registration of traffic or user), and acted as though they were P2P (Person to Person) messages. Choke programming was enabled by carriers to scout for mass SMS campaigns that sent messages with the same content to many telephones from Long Codes. Unfortunately, since long codes are cheap ($1/mo per number) and easy to obtain, spammers simply bought tons of them and wrote a routine to ‘round robin’ the traffic across long codes, and stay under the 1 MPS (message-per-second)limit, and other limits of the service. This technique is called “Snowshoeing”. Later this year, long codes will be sunsetted by the telecoms. These numbers will need to be replaced with one of the other A2P channels.

Toll Free Number (TFN)

For some time, an A2P sender has had an alternative in the form of a TFN (Toll Free Number, 800, 888, etc) to circumvent some of the chokes and filters. Use of a TFN requires some level of registration for “high throughput” – up to 200 MPS. Without registration, a TFN is restricted to 3 MPS. Registration of a TFN costs in the neighborhood of $500, and the cost to retain a high throughput TFN can range between  $200-$1500/mo. TFNs are best for ‘steady’ traffic flow.


What if you are a legit company, sending mass SMS traffic that subscribers really want? Is there a way to do it right? Yes, of course there is! Many companies do it today. These companies use the gold standard in A2P SMS messaging: Short Codes.

Short codes have been around since 2006 as a channel allow subscribers to easily send a text an application and initiate an A2P SMS conversation. This channel uses an easy-to-remember short (5 or 6 digit) number. To obtain a short code, companies are required to undergo a detailed registration of the client use case and traffic to be sent. Short codes are a limited resource, exactly because of the short nature of their numbering plan. At either five or six digits, the maximum number of available short codes are as follows:

 5 digit: 10000 to 99999 = 99,999 available numbers

6 digit: 100000 to 999999 = 999,999 available numbers

TOTAL – 1,099,998 Available short-code numbers

So, there is only about 1.1 million in the United States -- they are a scarce commodity. If they were a buck each (like long codes), companies would buy loads of them for everything under the sun. But they are not a buck each. On the contrary, they are thousands of dollars each to setup, and hundreds or thousands a month to retain. They do, however allow a company to send bulk traffic without the telecoms choking and filtering traffic, since their use case is pre-approved and closely monitored.

From this situation, arose the “shared short code”. This was a method where companies would gang up through a service provider and legitimately share a short code. Say someone has a radio commercial, and they are selling the “best plunger ever”. The little plunger company could not afford a dedicated short code, but they found a vendor that farms out a short code, 12345, as shared. They arrange to ask the radio audience to text “PLUNGER” to 12345. Everything’s great, right? Well, it was, until shared short codes were abused by spammers. Say the short code 12345 was vetted, and permission was granted to use it as a shared short code. Then the vendor began selling its use to multiple companies. The plunger app probably would not bother anyone and would indeed constitute a valid use case. But the code’s use was also sold to some other company – and they used it to blast out tons and tons of urgent messages about auto warranties (UGH!).


Because of these developments, the carriers are sunsetting share short codes as a valid use case starting 6/1/2021. Shared short codes will no longer be permissible after that date. Short codes will need to be used by individual organizations, and an in-depth analysis of each use case will be done by the vendor before the code is granted. The carriers will police the use of short-codes via algorithms, and look for abuse. Setting up new individual short codes might cost over $2000 for one-time registration and carrier fees, $1000 per month, and take 2-3 months to provision. Short codes will cost more per-message compared to other channels, depending on carrier fees. Short Codes come with a throughput of 100 MPS and up, depending on a ‘trust score’ that is based on the company size, nature of traffic and other considerations. Short codes are best for clients who do high-volume marketing and mass alerts.


So, some clients have been left orphaned. Clients who used shared short codes to send authentic messaging and reminder traffic can no longer rely on that channel. Others, that used long codes will need to seek an approved, high volume channel that doesn’t come with the price tag of dedicated Short Codes. For this reason, the carriers came up with 10DLC.

10DLC represents a compromise between the largely unsupervised long code of the past and the highly regulated short code. The service uses the old ‘local phone number’ format of long codes (I.E. 212-334-1346). 10DLC numbers are cheap to obtain ($1/number/mo), can be obtained in days rather than months.

10DLC service takes a different approach to registration fees. Registering a ‘brand’ to be used on 10DLC costs $4, but each campaign sent via this number requires an individual registration fee of between $2 and $10. Throughput from between <1 and 10 MPS can be obtained depending on the registration. 10DLC is targeted at companies that wish to conduct transaction messages with a local feel, and with some of the flexibility and cost savings of the old long code.

So the SMS A2P landscape will be changing this year, especially in regard to shared short codes and long codes.

ATI has long been a trusted partner to organizations that wish to use SMS for mass notification and transactional, two way messaging. Reach out to Patrick Bahar ( for more information on how ATI helps clients leverage SMS using the StreamWrite PORTALS platform.