Business Texting Without 10DLC: How iMessage Numbers Work

What is 10DLC, and who has to register?

10DLC means "10-digit long code": an ordinary US phone number used to send application-to-person (A2P) texts. US carriers require A2P SMS and MMS from these numbers to be registered, with a brand (the business) and one or more campaigns (what the messages are for). Twilio's A2P 10DLC overview puts it plainly: "Anyone sending SMS/MMS messages over a 10DLC number from an application to the US must register for A2P 10DLC." When we checked on October 8, 2026, Twilio blocked a message from a 10DLC number with no approved campaign with error 30034.

Registration costs money and time. These are Twilio's published figures; other SMS providers set their own.

Registration also sets your daily volume. When we checked on October 8, 2026, Twilio's overview listed daily caps to T-Mobile by brand type, for example 1,000 segments a day for a Sole Proprietor brand.

Why don't iMessage sends need 10DLC registration?

Because an iMessage is not an SMS or MMS. Apple's support page on the difference between iMessage, RCS and SMS/MMS says "With iMessage, messages can be sent to another iPhone or another Apple device over Wi-Fi or cellular-data networks," while "To use SMS/MMS on an iPhone, you need a text-messaging plan that supports these services." 10DLC registration is the carriers' system for A2P SMS and MMS on long codes. A message that travels as iMessage does not pass through that SMS path, so there is no brand or campaign to register for it.

On ZeroSettle this means you sign up, pay and send: the signup at portal.zerosettle.io has no carrier brand or campaign registration step. Your number is a real phone number on real iMessage, running on Apple hardware we operate for you in a server facility, and your code reaches it through a REST API and HMAC-SHA256 signed webhooks (see the ZeroSettle iMessage API page).

"No 10DLC" does not mean "no rules". Apple runs iMessage and can filter a number that behaves like spam, ZeroSettle suspends lines used for unsolicited messaging, and consent law applies to the message whatever network carries it. This guide explains how the channels work; it is not legal advice.

How does SMS on 10DLC compare with an iMessage number?

The two routes differ in what you register, who you can reach and how the message looks. Twilio stands in for SMS providers here because it publishes its rules and prices.

For a fuller comparison of cost, reach and reliability, see ZeroSettle vs Twilio.

What happens when the recipient isn't on iMessage?

On ZeroSettle, nothing is sent. Before the first message to a new contact goes out, the line asks Apple whether that phone number or email address is on iMessage. If it isn't, the API answers 422 with error code not_on_imessage; the docs say "Nothing was sent or stored, and it doesn't use a new-contact slot." The send docs are explicit that "there is no SMS or email fallback."

Apple lists the reasons a message goes green instead of blue, including "The person that you sent the message to doesn't have an Apple device" and "iMessage is turned off on your device or on your recipient's device." Those people need another channel: email, chat in your app, or SMS through a provider that sends it. Some iMessage providers do fall back to SMS or RCS (as of October 2026, Sendblue, Linq and Blooio said so on their own sites). That SMS leg is carrier SMS, so ask the provider how it handles carrier registration for it.

If you already send SMS, you can keep it for people without iMessage and add an iMessage number for iPhone users. Moving business texting from SMS to iMessage covers running both, introducing the new number and carrying opt-outs across.

Does TCPA consent still apply to iMessage?

Yes; plan as if it does. Skipping carrier registration changes the paperwork, not the law. ZeroSettle's compliance docs warn that in the United States, "texting a consumer without their prior express consent carries statutory damages of $500 to $1,500 per message," that "Marketing texts need written consent" and that "the National Do Not Call Registry applies." Canada, the UK and EU, and Australia have their own consent rules.

In practice, per the same docs:

1. Text only people who gave you their number for this purpose, and keep the record.
2. Say who you are in your first message.
3. Honor STOP immediately. ZeroSettle enforces it for you: a text with the word "stop" or an opt-out phrase blocks every number on your account from that person until they text START.
4. Send nothing promotional before 8 am or after 9 pm in the recipient's time zone.

iMessage marketing and TCPA consent: a practical guide goes deeper, and how STOP and opt-outs work on a ZeroSettle line covers exactly what is blocked.

What limits apply on a ZeroSettle iMessage number?

Instead of carrier registration tiers, ZeroSettle limits who a number can message first. These limits protect the number from being filtered; the docs call them "a floor, not a licence", so they never replace consent.

• New contacts: 5 a day per number on Pro; 50 a day and 3 per 15 minutes per number on Growth. People who text first, and ongoing conversations, are never limited. Over the limit, the API answers 429 new_contact_limit.
• Unanswered messages: at most 2 to a contact who has never replied (403 awaiting_reply).
• Attachments: photos, videos, voice messages and polls only to contacts who have replied at least once.
• Volume with known contacts: up to 10,000 messages a day per number, sent and received.

Pro opens 5 new contacts a day per number, fewer than the 30–50 most $99+ plans allow; people who text first are never limited.

What does an iMessage number cost compared with SMS on 10DLC?

ZeroSettle Pro is $49/month for a dedicated iMessage number that can message first. No managed iMessage API we checked publishes a lower price for a dedicated number (checked October 25, 2026). Courio also lists $49 (Starter: 500 outbound/month, then $0.02/message). Pro is $49/month flat, no per-message fees on API texts, with no setup fee, month to month, and a 30-day money-back guarantee. Growth is $599/month for 3 numbers that work as one, plus $199 a month per extra number.

SMS on 10DLC is billed differently: per segment, in and out, plus carrier fees, the number and registration (see the table above). By our arithmetic from Twilio's published rates, one outbound segment to a Verizon customer costs $0.0133 ($0.0083 + $0.005), so 1,000 outbound segments cost $13.30 before the number, inbound messages and registration fees. At low volume SMS costs less; the flat price matters more as threads get longer, as long as new conversations fit Pro's limits.

Cheaper iMessage options exist if you accept a shared number or run your own hardware. What a dedicated iMessage number costs at each provider and iMessage API pricing compared list them all, with sources.

When is SMS on 10DLC the better choice?

An iMessage number is not a full replacement for SMS. Choose SMS on a registered 10DLC number (or keep it alongside iMessage) when:

• You must reach everyone, including Android phones. ZeroSettle reaches only people on iMessage.
• You start many conversations a day. A Pro number opens 5 new contacts a day and a Growth number 50; consented alerts to thousands of new people a day fit SMS better.
• You send at low volume. At a few hundred messages a month, Twilio's per-segment pricing can cost less than $49, once registration is done.

An iMessage number fits when your customers mostly use iPhones, you want blue bubbles with your name and photo, and conversations run back and forth, such as support, sales follow-up and AI agents that people text first.

How we checked

On October 25, 2026 we read Twilio's A2P 10DLC overview, its A2P 10DLC brand registration page and its US SMS pricing page, Apple's two support pages cited below, and ZeroSettle's API docs. The 30034 error, the T-Mobile daily caps and the fallback claims of other providers come from our October 8, 2026 reading and were not re-checked. We tested nothing that needs a Twilio account. ZeroSettle's prices are from its signup page and docs; the competitor price check behind the "lower price" sentence is in iMessage API pricing compared.

We log changes to this page in the changelog.