Glossary · definition
What is 10DLC?
10DLC stands for 10-digit long code. It is the US system that lets businesses send texts from an ordinary local phone number, as long as they register who they are and what they will send. If you have received a verification code or an appointment reminder from a normal-looking US number, it probably came over 10DLC. Here is how it works and why it affects whether codes arrive.
Quick answer
What is 10DLC?
10DLC (10-digit long code) is a standard US phone number used for application-to-person texting, such as verification codes and alerts. Businesses must register their brand and each messaging campaign through The Campaign Registry before carriers deliver the traffic. Unregistered business texts from these numbers are blocked; Twilio, for example, has blocked them since September 1, 2023.
What does 10DLC mean?
A long code is any full-length phone number, as opposed to a 5- or 6-digit short code. In the US and Canada, numbers have 10 digits after the +1 country code, hence 10-digit long code. Phrases such as A2P 10DLC add one more idea: application-to-person, meaning texts sent by software rather than typed by a person.
Before 10DLC existed, business texts from ordinary numbers sat in a gray area. Carriers treated them like person-to-person messages and filtered them heavily, so legitimate senders and spammers looked the same. 10DLC created a sanctioned, registered path for that traffic.
How does 10DLC registration work?
A business registers through its messaging provider, which submits the details to The Campaign Registry, the central hub US carriers use for 10DLC. There are two parts: the brand (the company, with its legal and tax details) and one or more campaigns (each use case, such as two-factor authentication codes or delivery notifications, with sample messages and how users opt in).
Carriers then decide whether to accept the campaign and how much traffic to allow. The rules for consent, opt-outs and content come largely from the CTIA Messaging Principles and Best Practices (May 2023 edition). Unregistered traffic does not get through: Twilio's changelog says it has blocked US-bound messages from unregistered 10DLC numbers since September 1, 2023.
| 10DLC | Short code | Toll-free | |
|---|---|---|---|
| Looks like | A local 10-digit number | 5 or 6 digits | An 800-style number |
| Registration | Brand and campaign via The Campaign Registry | Lease from the Short Code Registry plus carrier approval | Toll-free verification |
| Volume | Low to high, set by carriers per campaign | Highest | Moderate |
| Voice calls | Yes, the same number can take calls | No | Yes |
Why does 10DLC matter to people receiving codes?
Most people never hear the term, but it explains several everyday surprises. Verification codes can come from different local numbers each time, because a company may send from a pool of registered 10DLC numbers. A code can be delayed or filtered when a sender's campaign is new, poorly registered or close to its volume limit.
It also explains why replying STOP works. Registered campaigns must honor opt-out keywords, so a STOP reply ends the messages from that sender to your number, including future codes, until you text START or UNSTOP.
Does 10DLC affect temporary numbers?
10DLC governs who sends business texts in the US, not who receives them. A temporary number receives codes from 10DLC senders like any other phone, as long as the line accepts SMS from that sender. On TempSMSVerify, you can try a US number with no risk: you are charged only if the code arrives, and the amount is refunded automatically if nothing arrives within up to 20 minutes. See /countries/usa.
FAQ
10DLC (10-digit long code): FAQ
What does 10DLC stand for?
10DLC stands for 10-digit long code: a standard 10-digit phone number in the US numbering plan used for business texting. You will often see it written as A2P 10DLC, where A2P means application-to-person, meaning messages sent by software, such as verification codes and reminders, rather than typed by a person.
Who needs 10DLC registration?
Any business or organization that sends application-to-person texts to US phones from a regular 10-digit number. That includes verification codes, alerts, reminders and marketing. Registration goes through the sender's messaging provider to The Campaign Registry. People texting friends from their own phones do not need it.
What happens if a business does not register for 10DLC?
Its texts are blocked or heavily filtered. Twilio, for example, says it has blocked US-bound messages from unregistered 10DLC numbers since September 1, 2023, and carriers can charge penalties for non-compliant traffic. That is one reason a code from a small company can fail to arrive while codes from large apps work.
What is the difference between 10DLC and a short code?
A short code is a 5- or 6-digit number leased from the US Short Code Registry and approved carrier by carrier, built for the highest volumes. 10DLC uses a normal local number, is registered through The Campaign Registry and suits low to high volumes. A 10DLC number can also take voice calls; a short code cannot.
Why do my verification codes come from different numbers?
Many companies send codes from a pool of registered 10DLC or toll-free numbers to spread traffic and keep delivery fast. Each code may arrive from a different local number. That is normal, but check the message content: a genuine code text never asks you to call back, pay or share the code with anyone.
Does 10DLC apply outside the United States?
No. 10DLC is a US framework built by US carriers and the messaging industry. Other countries handle business texting with their own rules, such as sender ID registration in many markets. Canada shares the +1 country code but runs its own messaging rules, so check local requirements before sending there.
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