A2P 10DLC registration

A2P 10DLC is the US carrier framework for application-to-person SMS from long-code numbers. Without it, outbound SMS from a 10-digit long code gets heavily filtered or dropped — often silently.

Do you need to register?

Yes, if any of:

• You send SMS from a US long code (most OpenPhn setups).
• You use OpenPhn's SMS templates on any number.
• Your Twilio subaccount is sending US A2P traffic.

Toll-free numbers have their own (simpler) verification track. SMS to short codes is not what we do here.

What you register

Two layers:

1. Brand — your legal entity. Name, EIN (or equivalent for non-US), industry, stock symbol if applicable. One-time.
2. Campaign — per use-case. Description, sample messages, call-to-action opt-in language, opt-out keyword support. One per traffic pattern (marketing vs notifications vs 2FA).

How OpenPhn handles it

OpenPhn-provisioned numbers (inbound, via our managed Twilio subaccount):

• We register our platform as the brand.
• Each customer has a sub-brand tied to their tenant.
• You fill out a sub-brand form in the dashboard. We file it.
• Campaign approval typically takes 1–3 business days.

BYO Twilio numbers (outbound, on your own Twilio account):

• Registration is on you. OpenPhn doesn't have access to file on your behalf.
• Follow Twilio's 10DLC registration flow in the Twilio console.
• Once approved, assign the campaign to the number OpenPhn is using.

What happens without registration

• First week: reduced throughput, elevated carrier filtering.
• After ~30 days: most major carriers (T-Mobile especially) silently drop unregistered A2P traffic. You see status: "sent" in Twilio but never delivered.

Useful links

• Twilio's 10DLC overview
• Campaign registry