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Senddio glossary · Application-to-Person, 10-Digit Long CodeLast reviewed: May 2026

What is A2P 10DLC?

A2P 10DLC (Application-to-Person, 10-Digit Long Code) is the United States carrier registration system for any application that sends SMS messages from a standard 10-digit phone number. Carriers require every business sender to register their brand and the type of messaging they will do, so that legitimate traffic gets prioritised and spam gets filtered.

How A2P 10DLC works in plain English

You register your business identity with The Campaign Registry (TCR), which is the US carrier consortium's database. You then register each "campaign" describing the kind of messages you send — for example, transactional OTPs, marketing promotions, or customer-care replies. Once approved, your numbers get higher throughput and better deliverability.

Why A2P 10DLC matters

Without 10DLC registration, US carriers may rate-limit your messages, reject them, or charge premium per-message fees. Unregistered traffic also has poor deliverability because carriers cannot distinguish you from spammers.

The pain of doing it yourself

Brand registration takes a few days; campaign registration can take one to three weeks, with rejections common when the use case description is not precise enough. The forms ask for opt-in language, message samples, and proof of business identity.

How Senddio handles 10DLC

Senddio holds the carrier relationship and absorbs the registration overhead for typical transactional use cases. For most teams, this means zero paperwork. Enterprise customers who need their own brand registration can do that on top, with Senddio guiding the application.

Related terms
OTP BSP
FAQ

A2P 10DLC — FAQ

For typical transactional sending in the US, no — Senddio absorbs the registration overhead. For high-volume, branded, or marketing use cases, registering your own brand may still make sense, and Senddio can guide you through it.

No. A2P 10DLC is a US-specific system. Other countries have their own sender-ID and registration regimes, and Senddio handles those separately as part of country routing.

In the US, yes — carriers actively rate-limit unregistered traffic, which causes deliverability and delay problems. Senddio routes through registered infrastructure so this is not a concern for most teams.

Senddio handles the boring parts of A2P 10DLC for you.

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