> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pilotstatus.com.br/llms.txt
> Use this file to discover all available pages before exploring further.

# WhatsApp Business Calling — Overview

> Receive and make WhatsApp voice calls through the Pilot Status API — signaling-only SDP relay, browser softphone, and Meta-side billing.

WhatsApp Business Calling lets you place and receive **voice calls** with your customers over WhatsApp, through the `/v1/calls*` API.

## Supported providers

Calling works on **two** provider types — and behaves differently on each:

| Provider                                    | What it is                               | Media model                                                                                                                                  |
| ------------------------------------------- | ---------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------- |
| **META** (Meta Cloud API)                   | Official WhatsApp Business number        | **Signaling-only** — Pilot Status relays SDP (RFC 8866); audio flows **browser ↔ WhatsApp** directly over WebRTC                             |
| **EVO\_GO** (Pilot Status web / unofficial) | A number connected via QR (non-official) | **Server-side media** — no SDP; audio is handled on the server (SRTP/Opus). You push audio or open a realtime stream via dedicated endpoints |

<Warning>
  Any other provider (Evolution v2, etc.) returns `400 FEATURE_NOT_SUPPORTED`. The error message: *"Calling is only supported for Meta Cloud API and Pilot Status (web) numbers."* An EVO\_GO number that is not connected returns `409 WHATSAPP_INSTANCE_NOT_CONNECTED`.
</Warning>

"Pilot Status (web) numbers" **are** the EVO\_GO numbers — there is no separate unofficial calling provider.

## Call types

| Type                              | Who starts it          | Billing                                                                                                                                             |
| --------------------------------- | ---------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------- |
| **BIC** — Business-Initiated Call | You call the customer  | On META, billed by **Meta directly on your WABA** (per minute, 6-second pulses, only when answered). On EVO\_GO there is no Meta per-minute charge. |
| **UIC** — User-Initiated Call     | The customer calls you | Free                                                                                                                                                |

Pilot Status **does not charge** anything for calls.

## Capability support by provider

| Capability                        | Endpoint                                   |            META           |       EVO\_GO      |
| --------------------------------- | ------------------------------------------ | :-----------------------: | :----------------: |
| Place a call (BIC)                | `POST /v1/calls`                           |  ✅ SDP offer **required** |    ✅ **no SDP**    |
| List calls                        | `GET /v1/calls`                            |             ✅             |          ✅         |
| Get one call                      | `GET /v1/calls/{callId}`                   |             ✅             |          ✅         |
| Accept (UIC)                      | `POST /v1/calls/{callId}/accept`           | ✅ SDP answer **required** |    ✅ **no SDP**    |
| Pre-accept                        | `POST /v1/calls/{callId}/pre-accept`       |             ✅             |          ❌         |
| Reject                            | `POST /v1/calls/{callId}/reject`           |             ✅             |          ✅         |
| Terminate / hang up               | `POST /v1/calls/{callId}/terminate`        |             ✅             |          ✅         |
| Play an audio file into the call  | `POST /v1/calls/{callId}/play`             |             ❌             | ✅ **EVO\_GO-only** |
| Realtime media session (PCM16 WS) | `POST /v1/calls/{callId}/realtime-session` |             ❌             | ✅ **EVO\_GO-only** |
| Get / update calling settings     | `GET`·`PUT /v1/calls/settings`             |             ✅             |          ❌         |
| Get call permissions              | `GET /v1/calls/permissions`                |             ✅             |          ❌         |
| Request call permission           | `POST /v1/calls/permissions/request`       |             ✅             |          ❌         |

A capability that a provider doesn't support returns `400 FEATURE_NOT_SUPPORTED`.

## How each provider handles media

### META — signaling only

Pilot Status relays the SDP; audio flows **browser ↔ WhatsApp** directly. Your WebRTC client produces the SDP offer/answer. There is nothing server-side to play into, so `play` and `realtime-session` do not apply. The dashboard **/chat** page includes a built-in browser **softphone** on Meta numbers.

### EVO\_GO — server-side media (no SDP)

`POST /v1/calls` and `/accept` take **no `sdp`** — the call connects and audio is processed on the server. You then drive audio with the two EVO\_GO-only endpoints:

* `POST /v1/calls/{callId}/play` — the backend downloads your audio file (through an SSRF guard) and plays it into the call.
* `POST /v1/calls/{callId}/realtime-session` — opens a full-duplex **PCM16 WebSocket** session. The returned `wsUrl` is on the public Evolution GO host and its token is single-use with a short (\~2 min) TTL; connect to it directly (it is not proxied through the API).

EVO\_GO numbers need no BIC **permission** grant and have no calling **settings** surface (those are Meta concepts).

## Migration / compatibility layer

If you already integrate with Evolution GO, the compatibility layer proxies the GO `/call/*` endpoints (start, answer, reject, hangup, list, get, media/play, media/realtime/session) — point your base URL at `/api/layer/evolution-go/` and your existing GO calling code keeps working. The realtime WebSocket (`/call/media/realtime/ws/*`) is reached **directly** on the public GO host (the HTTP layer does not upgrade WebSockets); GO frontend/manager routes are not proxied.

## Follow call progress with webhooks

Subscribe to `call.ringing`, `call.connected`, `call.ended` (includes `duration` in seconds when answered), `call.missed`, and `call.permission_updated`. Normalized `call.*` events fire for both META and EVO\_GO (Pilot Status web) numbers.

## Next steps

<CardGroup cols={2}>
  <Card title="Calls API Reference" icon="phone" href="/api/calls/endpoints">
    Every endpoint, parameters, and per-provider behavior.
  </Card>

  <Card title="Voice Calls Guide" icon="book-open" href="/guides/voice-calls">
    Step-by-step: place a call, answer, permissions, softphone.
  </Card>
</CardGroup>