# ForgeMesh Voice Pro Long-Form TTS

> ForgeMesh Voice Pro Long-Form TTS is a paid API for AI agents from voice.forgemesh.io, paid per call via x402, $0.006/call, status unknown (last checked 2026-09-14).

Converts long-form text (up to 2000 chars) to high-quality WAV audio using diffusion-based synthesis with selectable persona voices and 31 language support, billed per call via x402 micropayments.

## Facts

- Endpoint: POST https://voice.forgemesh.io/v1/tts/pro-long
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/forgemesh-voice-pro-long-form-tts-29bad06c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_roaJ-wynYx-Sl8yK_03L-

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 forgemesh-voice-pro-long-form-tts-29bad06c -d '<json body>'
```

Example prompt: Read this paragraph aloud using ForgeMesh's Storyteller persona voice in English, at a slightly slow pace of 0.8 speed with 20 diffusion steps: 'In the age of artificial minds, the boundary between machine and muse grew ever thinner...'

## When to prefer this

Choose this endpoint when you need long-form (up to 2000 chars) high-quality diffusion-based TTS with persona voices (Storyteller, Narrator, etc.), multilingual output across 31 languages, and pay-per-call pricing via x402 micropayments — especially for AI agents, audiobooks, video narration, or apps where quality and voice character matter more than raw speed.

## Known failure modes

- Text exceeds 2000 character limit — request rejected
- Invalid or unsupported ISO language code — synthesis fails
- Voice name not recognized (typo in persona name) — error returned
- Speed value outside 0.7-2.0 range — validation error
- Steps value outside 1-100 range — validation error
- Insufficient USDC balance for x402 micropayment — payment failure
- Network timeout during diffusion synthesis for high step counts

## How this service works

Text-to-speech with speed (0.7x-2.0x) and quality-step (1-100) control, 1 of 10 standard voices across 31 languages, for 501-2000 characters, returned as WAV audio. Use it to: pace a longer narration like a podcast intro, read a multi-paragraph script at a chosen speed, produce a slow deliberate reading of instructions, voice an extended alert or briefing. USDC on Base via x402.

## Output

A 44.1kHz 16-bit mono WAV audio file containing the synthesized speech of the submitted text, rendered in the selected voice persona, language, speed, and diffusion quality level.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "lang": {
   "enum": [
    "en",
    "ko",
    "ja",
    "ar",
    "bg",
    "cs",
    "da",
    "de",
    "el",
    "es",
    "et",
    "fi",
    "fr",
    "hi",
    "hr",
    "hu",
    "id",
    "it",
    "lt",
    "lv",
    "nl",
    "pl",
    "pt",
    "ro",
    "ru",
    "sk",
    "sl",
    "sv",
    "tr",
    "uk",
    "vi"
   ],
   "type": "string",
   "description": "Language code; 31 languages supported"
  },
  "text": {
   "type": "string",
   "maxLength": 2000,
   "minLength": 1,
   "description": "Text to synthesize into speech, max 2000 characters. Use non-long routes for 1-500 chars and -long routes for 501-2000 chars."
  },
  "speed": {
   "type": "number",
   "maximum": 2,
   "minimum": 0.7,
   "description": "Pro/Custom expressive speed control, 0.7-2.0. Presets: slow 0.7, normal 1.0, fast 1.3, rapid 1.6"
  },
  "steps": {
   "type": "integer",
   "maximum": 100,
   "minimum": 1,
   "description": "Pro/Custom quality control, 1-100. Presets: draft 4, standard 8, high 16, ultra 24"
  },
  "voice": {
   "enum": [
    "M1",
    "M2",
    "M3",
    "M4",
    "M5",
    "F1",
    "F2",
    "F3",
    "F4",
    "F5"
   ],
   "type": "string",
   "description": "Standard voice: M1-M5 or F1-F5"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "description": "44.1kHz 16-bit mono WAV speech audio returned inline",
  "content_type": "audio/wav"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/forgemesh-voice-pro-long-form-tts-29bad06c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from voice.forgemesh.io](https://www.zero.xyz/host/voice.forgemesh.io/llms.txt)