A2P 10DLC

A2P 10DLC is the US registration regime for application-to-person messaging sent from ordinary ten-digit long codes. It governs SMS rather than voice, and it requires registering the brand and each campaign before messages are reliably delivered.

It matters to outbound teams because dialers increasingly send SMS alongside calls, and unregistered traffic is filtered or blocked rather than merely rate-limited. Registration involves identifying the business, describing the campaign and accepting throughput limits tied to a trust score.

It is distinct from anything governing voice — STIR/SHAKEN attests calls, 10DLC registers messaging — and the two are frequently conflated in vendor material.

The practical consequence for an outbound team is a lead time. Brand and campaign registration is not instant, throughput is capped by a trust score that starts low, and messages sent before registration completes are filtered rather than queued. A team planning to add SMS to a calling sequence should start registration well before it plans to send, and should ask whether the dialer registers on their behalf or expects them to arrive already registered.