---
title: "Enable calling on a number"
method: POST
path: "/v1/phone-numbers/{id}/whatsapp/calling"
tags: ["WhatsApp Calling"]
---

# Enable calling on a number

`POST /v1/phone-numbers/{id}/whatsapp/calling`

Enable WhatsApp Business Calling on a connected number. Configures
Meta calling.status=ENABLED with our Telnyx SIP endpoint, fetches and
stores the Meta-issued SIP password (encrypted), and snapshots the
customer's forward-to destination.

## Path parameters

- `id` string, required

## Request body

- object
  - `accountId` string, required
  - `forwardTo` string, required — tel:+E164 / sip:... / wss://... destination
  - `sipAuthUsername` string
  - `sipAuthPassword` string — Stored encrypted, never returned by any endpoint.
  - `recordingEnabled` boolean
  - `callIconCountries` string[]
  - `maxCallDurationSeconds` integer — Hard cap (seconds) on a forwarded call; the carrier hangs up both legs when it fires. Safety valve against dead-air billing when a destination hangs up but the signal is lost.
  - `forwardCallerId` 'business' | 'caller' — Caller ID presented to the forward destination. caller = the WhatsApp user's number (sip: destinations only; ignored on tel: forwards). Fixes AI-agent trunks that reject seeing the business number call itself.

## Response `200`

Calling enabled

- object
  - `success` boolean
  - `callingEnabled` boolean
  - `sipHostname` string
  - `forwardTo` string
  - `callerIdMode` 'business' | 'platform' — Caller ID the forward-leg callee sees on tel: forwards. business = this WhatsApp number; platform = a Zernio number (customer-brought number without verified caller ID).

## Other responses

- `400` — Invalid request (including forwardTo set to the number itself)
- `401` — Unauthorized
- `404` — Phone number not found
- `422` — Not eligible to enable calling: not on usage-based billing, or the number's messaging limit is below Meta's ~2,000-daily-recipient threshold (TIER_250). Warm the number up to raise the limit.

---

[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/versions/51932b099b2f/schema)