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

# Wixzel Voice

> APIs for AI voice agents. One key, one balance, every voice engine.

Build AI voice agents that call real phone numbers over **your own SIP trunks**.
No ElevenLabs key, no Deepgram key, no OpenRouter key — one Wixzel Voice key and a
prepaid balance, billed per second of what a call actually consumes.

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Four requests from nothing to a ringing phone.
  </Card>

  <Card title="API reference" icon="code" href="/api-reference">
    Every endpoint, with a playground you can fire real requests from.
  </Card>

  <Card title="Voice engines" icon="waveform" href="/voice-engines">
    Compose a pipeline, or hand the whole turn to one realtime model.
  </Card>

  <Card title="Billing" icon="receipt" href="/billing">
    How credit is reserved, spent and itemised.
  </Card>
</CardGroup>

## What it replaces

A voice agent normally means separate contracts, keys and invoices for
speech-to-text, the model, and speech synthesis — each with its own failure mode
and its own bill to reconcile.

<CodeGroup>
  ```bash Place a call theme={null}
  curl https://api.voice.wixzel.com/v1/calls \
    -H "Authorization: Bearer $WIXZEL_API_KEY" \
    -H "Idempotency-Key: $(uuidgen)" \
    -d '{
      "to": "+14155550100",
      "agent_id": "ag_01HXYZ"
    }'
  ```

  ```json Response theme={null}
  {
    "object": "call",
    "status": "queued",
    "session_id": "sip-4f2a…",
    "cost_micros": null
  }
  ```
</CodeGroup>

## Telephony stays yours

Calls run over a SIP trunk you already have. We do not resell minutes, so your
carrier rates and carrier relationship are unchanged — and there is no telephony
markup on your bill.