Zernio
Zernio
API Reference

SMS

Messaging

Send an SMS/MMSPOSTLook up carrier + line typeGETList SMS opt-outsGET

Number Setup

Enable SMS on a numberPOSTDisable SMS on a numberDELETEAdd number to SMS registrationPOST

Registrations

List carrier registrationsGETPre-check a carrier registrationPOSTStart a carrier registrationPOSTGet a carrier registrationGETCreate a registration share linkPOSTDeactivate a brand/campaign registrationDELETE

Registration Review

Appeal a rejected campaignPOSTReply to a change requestPOSTUpload opt-in form proof for an appealPOSTUpload opt-in form proofPOSTRe-send the sole-prop OTPPOSTSubmit the sole-prop OTPPOST

Sender IDs

List alphanumeric sender IDsGETCreate an alphanumeric sender IDPOSTDelete an alphanumeric sender IDDELETERequest a higher sender ID daily limitPOST
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SMS

Look up carrier + line type

Carrier name and line type (mobile / landline / voip / toll-free) for a number, plus smsReachable (landlines can't receive SMS). Use it to validate recipients before sending. Each lookup is billed by the carrier-data provider, so call it explicitly (e.g. pre-validating an opt-in list), not on every send.

GET
/v1/sms/lookup

Authorization

bearerAuth
AuthorizationBearer <token>

API key authentication: send your Zernio API key in the Authorization header, prefixed with Bearer.

In: header

Query Parameters

number*string

Number to look up (E.164; formatting is normalized).

Length8 <= length

Response Body

application/json

application/json

import Zernio from '@zernio/node';const zernio = new Zernio({ apiKey: process.env.ZERNIO_API_KEY });const { data } = await zernio.sms.lookupSmsNumber({  query: {    number: 'string',  },});console.log(data);
{  "phoneNumber": "string",  "carrierName": "string",  "lineType": "mobile",  "smsReachable": true}
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Send an SMS/MMS

Sends an SMS (or MMS when `mediaUrls` is set) from one of your SMS-enabled numbers. At least one of `text` / `mediaUrls` is required. Both numbers are normalized to E.164, so `from` matches regardless of formatting and replies thread into the same inbox conversation. US numbers must have an approved carrier registration (`/v1/sms/registrations`) before messages deliver. **Replies and delivery status arrive as webhooks**, not by polling: an inbound reply fires `message.received` with `platform: "sms"`, the first message of a new thread also fires `conversation.started`, and this message's own outcome fires `message.delivered` or `message.failed` (the latter carrying the carrier's error code). **Opted-out recipients:** a send to a number that replied STOP is refused with `409`, never silently dropped. **Idempotency:** send an `Idempotency-Key` header to make retries safe: same key + same body replays the original response instead of sending a second message; same key + different body returns 422; a key still in flight returns 409.

List SMS opt-outs

The recipients who opted out of SMS (replied STOP) across your numbers, most recent first. Compliance surface: you must be able to see and export your opt-out list. Read-only: a recipient is re-subscribed only by replying START. Pass `format=csv` to download a CSV instead of JSON.