A2P 10DLC

The US carriers' registration regime for application-to-person SMS sent from ordinary ten-digit numbers. Paged 2026-08-22 from twilio's compliance documentation and its published US SMS pricing — T3, because both are a vendor describing a system it participates in and sells access to. The registration mechanics and the rate card are first-party facts of the kind the ladder says T3 is for; the "lower filtering, higher throughput" benefit claim is the vendor's and is flagged below rather than repeated as a finding.

This is the baseline coverage edge 4 said the spoke was missing: per-message-pricing and rcs-business-messaging were being described against a channel no page here held.

What it is and why it exists

"Application-to-Person (A2P) messaging is SMS/MMS traffic in which a person is receiving messages from an application rather than another individual." 10DLC is a ten-digit long code — an ordinary US phone number.

The reason for the regime is stated plainly: "Ten-digit long code numbers in the US were originally designed for person to person (P2P) communication. These routes were unregulated, and in recent years have started seeing abuse from spam applications and unsolicited messaging." And the consequence: "Due to the increase in spam messages, many consumers have lost trust in SMS as a form of communication."

An open channel, abused, then gated. That sentence is the whole of this spoke's founding thesis, and here it is written by the party doing the gating.

The gate

Two registrations, in order.

Brand — "You provide information about who is sending these messages so that carriers know you are a legitimate sender." That is sender-verification by another name, one channel over.

Campaign — "You provide information about how end users can opt-in, opt-out, and receive help. It also involves providing a description of the purpose of your messages." A declared message purpose, approved before traffic flows, is what message-template approval does on WhatsApp. The mechanism differs — 10DLC approves the use case and WhatsApp approves the text — but both put a reviewer between a business and its customers.

Registration path depends on customer type (Direct Brand, ISV, or Sole Proprietor) and brand type, and the brand type sets the daily ceiling:

Unregistered traffic is not blocked at the documentation level; it is surcharged. "Customers who send messages from a Twilio 10DLC number but do not register will receive additional carrier fees for sending unregistered traffic." Registering, the docs say, "results in lower message filtering and higher messaging throughput" — a claim about carrier behaviour made by a reseller, with no filtering rate published on either side of it.

What a message costs

Twilio's US list price, read 2026-08-22 and re-read 2026-09-22 with every figure below unchanged. Long code, toll-free and short code all carry the same per-message rate; the carrier surcharge sits on top and varies by destination network.

Per-segment carrier fees on long-code SMS: AT&T $0.0035 · T-Mobile $0.0045 · Verizon $0.0045 · US Cellular $0.005, with inbound charged separately (Verizon's inbound is $0.007, higher than its outbound). A failed message costs $0.001 to process.

So a delivered US SMS segment lands around $0.012–$0.013 all-in, before registration and monthly campaign fees. A message longer than one segment costs that again per segment.

What the comparison shows

The gate is the same shape; the meter is not. WhatsApp's per-message-pricing charges by template category and by the recipient's country, makes customer-initiated conversation free inside the customer-service-window, and discounts by volume tier. The pricing is a policy instrument — the categories Meta considers legitimate get cheaper, marketing always pays. 10DLC does none of that. Every segment costs the same whatever it says, whoever started the conversation, and however much you send; the volume lever is a throughput ceiling rather than a discount, and the policy lever is registration rather than price.

Two channels, both gated, and the gate is doing different work: Meta uses billing to shape what gets sent, and the US carriers use approval to decide who may send at all and then charge a flat rate for the pipe. This spoke's line — "billing is policy" — turns out to be a WhatsApp property, not a property of business messaging. It rested on one channel, and now there is a second one to test it against, which is the finding rather than the rate card.

And the carrier is a party to it. Verizon charges more to receive a message than to send one; AT&T and T-Mobile charge different amounts for the same message. On WhatsApp there is one counterparty setting one price. Here the destination network prices your traffic after you have paid your provider, which is the structure the open question about RCS billing was guessing at.

Standing caveat

Every figure here is a dated snapshot from one reseller's list price. Carrier surcharges have been revised repeatedly, registration fees are set by a third party (The Campaign Registry) that this page does not source, and a different CPaaS will quote different numbers on the same carrier fees. Treat the structure as the finding and the amounts as an illustration.

Related

per-message-pricing · message-template · sender-verification · rcs-business-messaging · business-solution-provider · twilio · synthesis