# Onchain Router – Text-to-Speech (ElevenLabs Flash v2.5)

> Onchain Router – Text-to-Speech (ElevenLabs Flash v2.5) is a paid API for AI agents from llm.agenticfi.wtf, paid per call via x402, $0.002/call, status down (last checked 2026-09-15).

Converts text input to MP3 audio using ElevenLabs Flash v2.5, routed through a provider-neutral API with per-request USDC micropayment and durable on-chain receipt.

## Facts

- Endpoint: POST https://llm.agenticfi.wtf/v1/audio/speech
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/onchain-router-text-to-speech-elevenlabs-flash-v2-5-7e0f49ca
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TSnJWvkYUniYBW6LpT6sr

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 onchain-router-text-to-speech-elevenlabs-flash-v2-5-7e0f49ca -d '<json body>'
```

Example prompt: Read this aloud in the 'darian' voice at normal speed and give me an MP3: 'Welcome to our weekly product update. Here's what's new this sprint.'

## When to prefer this

Choose this endpoint when you need reliable, low-latency ElevenLabs-quality TTS with a specific named voice, want to pay per request in USDC without a monthly subscription, or require an auditable on-chain payment receipt. Prefer it over direct ElevenLabs API calls when operating in a crypto-native or agent payment infrastructure using x402. Not suited for batch processing of large documents or streaming real-time audio.

## Known failure modes

- Input text exceeds 2000 characters — validation error returned
- Speed value outside 0.7–1.2 range or not a multiple of 0.001 — schema validation failure
- Invalid voice alias not in enum — rejected at input validation
- Insufficient USDC balance for micropayment — 402 Payment Required before processing
- Audio URL may expire after a short TTL — agent must retrieve or cache promptly
- Model enum mismatch if additional models added later — currently only 'elevenlabs/flash-v2.5' supported

## How this service works

Text-to-speech generation · 24-hour encrypted capability URL · 0% service fee launch promotion

## Output

Returns a JSON object containing a speech ID, a time-limited signed URL pointing to the generated MP3 audio file, the model used, and a character usage count. The agent can pass the URL to a media player or downstream pipeline.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "input": {
   "type": "string",
   "maxLength": 2000,
   "minLength": 1
  },
  "model": {
   "enum": [
    "elevenlabs/flash-v2.5"
   ],
   "type": "string"
  },
  "speed": {
   "type": "number",
   "maximum": 1.2,
   "minimum": 0.7,
   "multipleOf": 0.001
  },
  "voice": {
   "enum": [
    "darian",
    "talia",
    "elara",
    "baxter",
    "eldrin",
    "kellan",
    "elowen",
    "kaelen",
    "lawrence",
    "alicia",
    "maisie",
    "warren",
    "jade",
    "eddie",
    "caleb",
    "sawyer",
    "finley",
    "florence",
    "wyatt",
    "bella"
   ],
   "type": "string",
   "description": "Optional public alias; omission uses the selected model's default voice."
  },
  "response_format": {
   "enum": [
    "mp3"
   ],
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "spch_example",
  "data": [
   {
    "url": "https://llm.agenticfi.wtf/v1/media/audio/example?access=capability"
   }
  ],
  "model": "elevenlabs/flash-v2.5",
  "usage": {
   "input_characters": 19
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onchain-router-text-to-speech-elevenlabs-flash-v2-5-7e0f49ca/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from llm.agenticfi.wtf](https://www.zero.xyz/host/llm.agenticfi.wtf/llms.txt)