SMS
Send and receive SMS and MMS from your numbers, with US carrier registration handled
Send and receive text (and picture) messages from your phone numbers. Replies thread into the same inbox as your other channels. In the US, a number needs an approved carrier registration before messages deliver; Zernio runs that registration flow for you.
SMS is available on the Usage plan only. In the US, messages will not deliver from a number until its carrier registration (10DLC or toll-free) is approved. Register early: approval is asynchronous and can take time.
Quick Reference
| Property | Value |
|---|---|
| Message types | SMS (text) and MMS (media) |
| From | Any SMS-enabled number on your account |
| Number format | E.164 (normalized automatically) |
| Replies | Thread into the unified Inbox |
| US requirement | Approved 10DLC or toll-free registration |
| Registration reuse | One approval covers many numbers (no repeat brand fee) |
| Idempotency | Supported via Idempotency-Key header |
How it fits together
- Get an SMS-capable number. Not every number can text; check SMS support when you search (
sms=true) or port in. - Enable SMS and register. Enable SMS on the number, then run the US carrier registration. Already have an approved registration? Reuse it and skip the fee.
- Send. Send SMS or MMS, handle opt-outs, and read replies in the Inbox.
In This Section
Carrier Registration
10DLC and toll-free registration, sharing, and reuse
Sending
Send SMS/MMS, handle opt-outs, and look up numbers
Related Endpoints
- Send an SMS/MMS - Send a message from your number
- Start a carrier registration - Begin 10DLC or toll-free registration
- Add a number to an existing registration - Reuse an approval
- List carrier registrations - Track registration status
- List SMS opt-outs - Recipients who opted out