---
title: "Start SMS Enrollment"
method: POST
path: "/user-authenticators/sms"
tags: ["SMS"]
---

# Start SMS Enrollment

`POST /user-authenticators/sms`

Start a challenge to enroll a new SMS authenticator for a given phone number.

## Request body

- object
  - `phoneNumber` string, required — The user’s phone number in E.164 format.
  - `smsChannel` 'DEFAULT' | 'WHATSAPP'

## Response `200`

OK

- object
  - `userAuthenticatorId` string — The ID of the SMS authenticator which has been created but not yet verified.
  - `userId` string

## Other responses

- `400` — Invalid Request
- `401` — Unauthorized
- `404` — Not Found
- `429` — Too Many Requests

---

[API](https://skmtc.net/authsignal/apis/call-connect-api.md) · [All operations](https://skmtc.net/authsignal/apis/call-connect-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/authsignal/call-connect-api/versions/5604d744e3ad/schema)