---
title: "Start caller-ID verification for a customer-brought number"
method: POST
path: "/v1/phone-numbers/{id}/whatsapp/caller-id-verification"
tags: ["WhatsApp Calling"]
---

# Start caller-ID verification for a customer-brought number

`POST /v1/phone-numbers/{id}/whatsapp/caller-id-verification`

Customer-brought (BYO) WhatsApp numbers cannot present themselves as
caller ID on `tel:` call forwards until verified (carrier
anti-spoofing); until then forwarded calls show a Zernio number
(`callerIdMode: platform` on the calling config). This sends a
one-time code to the number by SMS or voice call. Re-POST to resend.
Zernio-purchased numbers never need this and get a 400.

## Path parameters

- `id` string, required

## Request body

- object
  - `method` 'sms' | 'call'

## Response `200`

Code sent (or the number was already verified)

- object
  - `verified` boolean
  - `codeSent` boolean
  - `method` 'sms' | 'call'

## Other responses

- `400` — Invalid request
- `401` — Unauthorized
- `404` — Number not found
- `429` — Too many verification attempts for this number; wait before retrying

---

[API](https://skmtc.net/zernio/apis/zernio-api.md) · [All operations](https://skmtc.net/zernio/apis/zernio-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/zernio/zernio-api/revisions/d0ab3b4eb0ae/schema)