# xAI Grok Voice Text-to-Speech

> xAI Grok Voice Text-to-Speech is a paid API for AI agents from audio.withzero.xyz, paid per call via MPP, $0.00174/call, status unknown (last checked 2026-09-13).

Converts text input into natural-sounding speech using xAI's Grok Voice model and returns a hosted WAV audio URL.

## Facts

- Endpoint: POST https://audio.withzero.xyz/api/v1/speech/grok-voice
- Price: $0.00174/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 3
- Provider: audio.withzero.xyz
- Website: https://audio.withzero.xyz
- Canonical page: https://www.zero.xyz/c/audio-withzero-xyz-xai-grok-voice-text-to-speech-5219a71b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_W-wnAWcZhJlwAWLyxIleS

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability audio-withzero-xyz-xai-grok-voice-text-to-speech-5219a71b -d '<json body>'
```

Example prompt: Can you read this aloud using xAI's Grok Voice: 'Welcome to our annual product launch. We're thrilled to share what we've been building.' Use the default voice.

## When to prefer this

Choose this endpoint when you specifically want xAI's Grok Voice model for text-to-speech synthesis, particularly if you need a hosted audio URL returned directly without managing file storage yourself. Prefer this over Google Gemini TTS or OpenAI TTS when you want xAI's voice characteristics or are comparing voice quality across providers.

## Known failure modes

- Text input exceeds 4000 characters — request rejected with validation error
- Empty or missing input field — returns 400 bad request
- Invalid or unrecognized voice identifier — may fall back to default or return error
- Service unavailable or xAI model downtime — 500 or 503 response
- Audio hosting failure — URL returned may be temporarily inaccessible

## How this service works

Convert text to natural-sounding speech with xAI's Grok Voice and return a hosted audio URL.

## Output

Returns a JSON object containing a hosted URL pointing to a WAV audio file (24kHz mono), the MIME type, file size in bytes, approximate duration in seconds, the model name used, and the USDC amount charged for the request.

## Example request

```json
{
 "input": "Welcome to our annual product launch. We're thrilled to share what we've been building.",
 "voice": "default"
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "example": {
  "input": "Hello from WithZero — this is a text to speech sample."
 },
 "required": [
  "input",
  "voice"
 ],
 "properties": {
  "input": {
   "type": "string",
   "maxLength": 4000,
   "minLength": 1,
   "description": "The text to convert to speech (1–4000 characters)."
  },
  "voice": {
   "type": "string",
   "default": "default",
   "maxLength": 64,
   "minLength": 1,
   "description": "Voice to speak with. Defaults to \"default\"."
  }
 },
 "additionalProperties": false
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "url",
  "mimeType",
  "sizeBytes",
  "seconds",
  "model",
  "price_usdc"
 ],
 "properties": {
  "url": {
   "type": "string",
   "description": "Hosted URL of the generated audio (WAV, 24kHz mono)."
  },
  "model": {
   "type": "string",
   "description": "The model that produced the audio."
  },
  "seconds": {
   "type": "number",
   "description": "Approximate duration of the generated audio in seconds."
  },
  "mimeType": {
   "type": "string",
   "description": "Content type of the generated audio."
  },
  "sizeBytes": {
   "type": "number",
   "description": "Size of the generated audio in bytes."
  },
  "price_usdc": {
   "type": "string",
   "description": "The amount charged for this request, in USDC."
  }
 },
 "additionalProperties": false
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/audio-withzero-xyz-xai-grok-voice-text-to-speech-5219a71b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from audio.withzero.xyz](https://www.zero.xyz/host/audio.withzero.xyz/llms.txt)