Glossary
A2P 10DLC
Also written: A2P messaging, 10DLC registration
Quick answer
What is A2P 10DLC?
A2P 10DLC is the registration system United States carriers require for application-to-person messaging sent over standard 10-digit long code numbers. Businesses register a brand and each messaging campaign. Without approved registration, messages to US numbers are heavily filtered or blocked entirely.
A2P stands for application-to-person — messages sent by software rather than typed by a human. 10DLC refers to standard ten-digit phone numbers, as distinct from short codes or toll-free numbers, which have their own regimes.
The requirement applies to transactional messages such as appointment reminders as well as to marketing, though the two are classified differently and follow different rules.
Registration is handled through The Campaign Registry, the body operating the 10DLC system on behalf of US carriers.
Registration is reviewed by carriers, and the timeline is genuinely outside any vendor’s control — it can take from days to a couple of weeks. This makes it the longest-lead item in most US GoHighLevel projects, and the reason experienced implementers submit it on day one rather than during launch week.
Common rejection causes are a mismatch between submitted business details and public records, or a campaign use case described inaccurately.
Related terms
- CRM AutomationCRM automation removes manual work from customer relationship management by automatically creating and updating contact records, moving deals between pipeline stages, triggering follow-up sequences, assigning tasks and notifying team members, based on defined triggers rather than someone remembering to act.
- GoHighLevelGoHighLevel is an all-in-one sales and marketing platform that combines CRM and pipelines, workflow automation, funnels and websites, calendars, email, SMS and phone calling in one system. It is aimed at marketing agencies and small businesses, and supports white-label reselling under an agency's own brand.
Services that use this
Get your business texting approved before it costs you leads
A2P 10DLC is the registration system US carriers require for application-to-person messaging over standard 10-digit numbers. It involves registering your brand and each messaging campaign. Without approved registration, messages to US numbers are heavily filtered or blocked outright, so it is mandatory rather than optional for US SMS.
Make sure the messages you automate actually arrive
Automated messages fail to deliver most often because the sending domain is not authenticated with SPF, DKIM and DMARC records, because a new sending domain or number was used at high volume without warm-up, because sender reputation has been damaged by complaints, or because required carrier registration was never completed.
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