# Grok TTS via Locus x402

> Grok TTS via Locus x402 is a paid API for AI agents from grok.x402.paywithlocus.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Converts text to speech using xAI's Grok models, with multiple voices, language support, and inline speech tags, billed per-call via x402 micropayment.

## Facts

- Endpoint: POST https://grok.x402.paywithlocus.com/grok/tts
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/grok-tts-via-locus-x402-654ef34c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jfqSt60_dT6g3Ip1XxM_b

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 grok-tts-via-locus-x402-654ef34c -d '<json body>'
```

Example prompt: Can you read this aloud using the warm 'ara' voice in English: 'Welcome to our platform. [pause] We're so glad you're here.' — give me the audio as an MP3.

## When to prefer this

Choose this endpoint when you need high-quality AI speech synthesis with multiple expressive voice options, multilingual support, and inline speech markup (pauses, laughs, whispers), especially in contexts where micropayment-per-call via x402/USDC is preferred over subscription billing. Prefer it over generic TTS APIs when you want access to xAI's Grok voice models specifically, or when building agent workflows that need pay-as-you-go audio generation without API key management overhead.

## Known failure modes

- Text exceeds 15,000 character limit — request rejected
- Invalid BCP-47 language code — may fall back to auto-detection or return error
- Unknown voice_id value — defaults to 'eve' or returns validation error
- Unsupported audio codec or sample rate in output_format — format error
- Payment failure or insufficient USDC balance — x402 payment rejected
- Service unavailable or xAI backend error — non-200 response

## How this service works

Locus public pay-per-use API

## Output

Returns a JSON object with a data field containing the synthesized audio (or a reference/URL to it), a payment confirmation showing 0.001 USDC settled, a request ID and status URL for tracking, and a success flag.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string"
  },
  "language": {
   "type": "string"
  },
  "voice_id": {
   "type": "string"
  },
  "output_format": {
   "type": "object",
   "additionalProperties": true
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {},
  "payment": {
   "scheme": "exact",
   "settledUsdc": "0.001000",
   "authorizedMaxUsdc": "0.001000"
  },
  "request": {
   "id": "00000000-0000-4000-8000-000000000000",
   "statusUrl": "/requests/00000000-0000-4000-8000-000000000000"
  },
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/grok-tts-via-locus-x402-654ef34c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from grok.x402.paywithlocus.com](https://www.zero.xyz/host/grok.x402.paywithlocus.com/llms.txt)