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Vapi is a platform for building voice agents. Kova plugs in as a custom voice: Vapi sends each utterance to a Kova endpoint and plays back the audio Kova returns.

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Configure your assistant

Set your assistant’s voice to Vapi’s custom-voice provider, pointed at the Kova Vapi endpoint with your chosen voice and API key. 
{
  "voice": {
    "provider": "custom-voice",
    "server": {
      "url": "https://api.kova.ai/v1/tts/integrations/vapi?voice=cal",
      "headers": {
        "x-api-key": "kova_sk_your_key_here"
      }
    }
  }
}
  • url: the Kova Vapi endpoint. Set the voice query parameter to any speaker id from /v1/tts/speakers (for example cal).
  • headers.x-api-key: your Kova API key from platform.kova.ai. Vapi sends it on every request; Kova validates and bills it.
Each Vapi voice maps to one Kova speaker. To offer multiple voices, create one custom-voice config per speaker, changing the voice query parameter.

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How it works

Vapi POSTs a voice-request for each utterance: 
{ "message": { "type": "voice-request", "text": "Hello from Kova.", "sampleRate": 24000 } }
Kova synthesizes the text and returns raw 16-bit mono little-endian PCM at the requested sample rate, which Vapi streams into the call. Supported sample rates: 8000, 16000, 22050, and 24000 Hz.

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Billing and errors

Usage is billed to the API key in the x-api-key header, the same as direct API calls. An invalid key returns 401; an account out of credits returns 402. Top up at platform.kova.ai/dashboard/billing.