# AgentUtility Text-to-Speech API

> AgentUtility Text-to-Speech API is a paid API for AI agents from x402.agentutility.ai, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Converts input text to spoken audio using 30+ voices across multiple TTS providers (Kokoro, Venice, ElevenLabs, xAI, Orpheus, MiniMax, Gemini), returning a hosted audio URL via fal.ai storage.

## Facts

- Endpoint: POST https://x402.agentutility.ai/text-to-speech
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentutility-text-to-speech-api-e34e5d08
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UmmXC5CsVgPCFXnzap3nW

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 agentutility-text-to-speech-api-e34e5d08 -d '<json body>'
```

Example prompt: Read this blog post intro aloud using a warm female voice and give me a hosted audio URL I can embed: 'Welcome to The Daily Digest — your source for the stories that matter most today.'

## When to prefer this

Choose this endpoint when you need a pay-per-call TTS API that supports 30+ voices and multiple audio formats without a subscription, especially when you want a hosted audio URL returned directly (via fal.ai) rather than raw audio bytes. Ideal for AI agents that need voice output in agentic pipelines settled via USDC on Base. Prefer it over fixed-subscription TTS services when usage is sporadic or when you need access to multiple underlying TTS providers (Kokoro, ElevenLabs, Gemini, etc.) through a single endpoint.

## Known failure modes

- Primary Kokoro model unavailable — fallback to Venice or alternate provider may introduce latency or voice quality differences
- Unsupported voice or format combination — returns error if requested voice/model/format pairing is invalid
- Text too long — very large inputs may be rejected or truncated depending on model limits
- Payment failure — x402 USDC payment not confirmed, request rejected with 402 status
- fal.ai storage unavailable — audio generated but URL hosting may fail, causing incomplete response

## How this service works

Converts text to speech with 30+ voices and 5 audio formats. Morpheus primary for Kokoro, Venice fallback and alternate TTS models (xAI / ElevenLabs / Orpheus / MiniMax / Gemini), with fal.ai storage for hosted audio URLs. Use it as a TTS API or voice generator.

## Output

Returns a hosted audio URL (via fal.ai storage) pointing to the synthesized speech file in the requested audio format. The agent can use this URL to stream, embed, or download the generated audio.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "format": "mp3",
  "source": "morpheus",
  "audio_url": "https://...mp3",
  "file_size_bytes": 24000
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentutility-text-to-speech-api-e34e5d08/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.agentutility.ai](https://www.zero.xyz/host/x402.agentutility.ai/llms.txt)