---
title: "Start SMS Challenge"
method: POST
path: "/challenge/sms"
tags: ["SMS"]
---

# Start SMS Challenge

`POST /challenge/sms`

Start a challenge when the user is already enrolled with at least one SMS authenticator.

## Request body

- object
  - `smsChannel` 'DEFAULT' | 'WHATSAPP'

## Response `200`

OK

- object
  - `challengeId` 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)