> ## Documentation Index
> Fetch the complete documentation index at: https://onextel-09023014.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# WhatsApp Voice overview

> Let customers call your business from inside WhatsApp, and have those calls arrive at your existing voice platform as ordinary SIP calls.

WhatsApp Voice lets your customers tap the call button in a WhatsApp chat and speak to your business.
OneXtel connects that call to the voice platform you choose, as a standard SIP call: your own IVR, a
contact-centre platform, any third-party voice platform, or a voice AI agent. You do not need to build
anything WhatsApp-specific.

<Info>
  WhatsApp Voice currently supports **inbound calls only**: a customer calls your business. Calling
  customers from your business over WhatsApp is not part of this release.
</Info>

## What you get

* **A call button in your WhatsApp chat.** Customers call your WhatsApp Business number without
  dialling a phone number or paying a call charge.
* **Calls delivered over SIP.** Your voice platform, whichever vendor it comes from, receives each
  call on a SIP trunk that you control, so it can run an IVR, route to agents, or hand the call to a
  voice AI agent exactly as it does for calls from the phone network.
* **Automatic fallback.** If your platform does not answer or rejects the call, the gateway tries your next
  trunk, such as a backup agent or a human queue.
* **Keypad input.** Customers can press keys during the call, and your platform receives them as standard
  RFC 4733 events.
* **No WhatsApp integration work on your side.** OneXtel handles the connection with Meta,
  the encryption, and the audio format conversion between WhatsApp and your platform.
* **Call records and monitoring.** Each call is recorded with its start, answer and end times,
  duration, result, and whether audio flowed in both directions. A timeline of the SIP messages for each
  call helps OneXtel troubleshoot quickly.

## How it fits together

<Frame caption="WhatsApp Voice: the path of an inbound call">
  <img src="https://mintcdn.com/onextel-09023014/RG2oUr-csQvHlduH/images/whatsapp-voice-architecture.svg?fit=max&auto=format&n=RG2oUr-csQvHlduH&q=85&s=665aa451eadb4e194bebdf689be5a90f" alt="A customer's WhatsApp call goes to Meta, then to the OneXtel WhatsApp Voice gateway over SIP on TLS with encrypted audio. The gateway delivers it to any third-party voice platform, including voice AI agents, over SIP and RTP." width="1200" height="600" data-path="images/whatsapp-voice-architecture.svg" />
</Frame>

OneXtel sits between Meta and your voice platform. Meta delivers the call to the OneXtel gateway.
The gateway answers Meta's authentication, anchors the audio, converts it to a format your platform
accepts, and forwards the call to your SIP trunk. See [How it works](/guides/whatsapp-voice/how-it-works)
for the full call flow.

## What it does not do

<AccordionGroup>
  <Accordion title="It does not provide the IVR or the agent desktop">
    The call menus, languages, speech handling and any integration with your backend systems run on your
    voice platform. WhatsApp Voice delivers the call to it.
  </Accordion>

  <Accordion title="It does not record calls">
    Meta provides no recording for WhatsApp calls. If you need recordings, record on your voice platform,
    where the call arrives as a normal SIP call.
  </Accordion>

  <Accordion title="It does not make outbound calls">
    Inbound only. Customers call you; you do not call them over WhatsApp.
  </Accordion>
</AccordionGroup>

## Cost

Meta does not charge for calls that customers place to your business. Commercial terms for the OneXtel
service are agreed with your account team.

## Next steps

<CardGroup cols={2}>
  <Card title="How it works" icon="diagram-project" href="/guides/whatsapp-voice/how-it-works">
    The path of a call, step by step.
  </Card>

  <Card title="Get started" icon="rocket" href="/guides/whatsapp-voice/getting-started">
    What you supply, and what OneXtel sets up.
  </Card>

  <Card title="Connect your voice platform" icon="phone" href="/guides/whatsapp-voice/connect-your-voice-platform">
    The SIP trunk your platform needs to provide.
  </Card>

  <Card title="Protocols and media" icon="sliders" href="/guides/whatsapp-voice/protocols-and-media">
    Transport, codecs, ports and headers.
  </Card>
</CardGroup>


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