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StableVoice Text-to-Speech API
x402
StableVoice Text-to-Speech API is a paid API for AI agents from stablevoice.dev, paid per call via x402, $1/call, status unknown (last checked 2026-09-13).
Generates speech audio from text using Chatterbox Turbo, Chatterbox, or multilingual Chatterbox models, delivering output into StableUpload audio slots via x402 micropayment protocol
Price / call$1
Success—
StatusUnknown
How this service works
Text-to-speech on Modal via x402 and MPP. Generate Chatterbox Turbo, Chatterbox, and multilingual Chatterbox speech into StableUpload audio slots.
Output
A reference or URL to a StableUpload audio slot containing the synthesized speech audio generated from the provided text using the selected Chatterbox model.
Example use cases
Example prompt
“Generate spoken audio for the text 'Welcome to our platform, we're glad you're here.' using the Chatterbox Turbo model and store it in a StableUpload audio slot.”
Technical details
Endpoint
POSThttps://stablevoice.dev/api/speechWhen to prefer
Choose this endpoint when you need high-quality Chatterbox-model TTS (including Turbo and multilingual variants) with automatic audio storage via StableUpload, and are operating in a pay-per-call x402 micropayment environment. Prefer over generic TTS APIs when you want Chatterbox-specific voice quality or need direct integration with the StableUpload storage ecosystem.
Side effects
- Payment failure — x402 micropayment of $1 USDC not authorized or insufficient funds
- Invalid model selection — unsupported Chatterbox model variant specified
- Text input too long — exceeds maximum character limit for synthesis
- Unsupported language — requested language not available in multilingual model
- StableUpload slot unavailable — storage destination cannot be allocated
- Server error on Modal compute infrastructure
Input
{
"text": "Hello, this is a test of the speech synthesis system. The weather today is sunny and pleasant.",
"type": "stablevoice-speech",
"model": "chatterbox-turbo",
"voice": "Lucy",
"format": "wav",
"output": {
"publicUrl": "https://stableupload.example.com/audio/test-output-12345.wav",
"uploadUrl": "https://stableupload.example.com/upload/test-output-12345"
},
"language": "en",
"clientRequestId": "qa-test-001"
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| text | string | Text to synthesize, max 2500 characters. |
| type | string | |
| model | string | Self-hosted Modal model. chatterbox-turbo is fastest; chatterbox adds expressive controls; chatterbox-multilingual supports 23 languages. |
| voice | string | Bundled reference voice. Match to the character's identity using `voiceGuide` from /api/voices — each voice carries an accent/ethnicity tag (Indian, Australian, Slavic, Black, Latina, American, older country) and a casting cue. Default Lucy is a neutral North American female. Ignored only when referenceAudioUrl is supplied. |
| format | string | |
| output | object | Reserved StableUpload output slot for the generated audio. |
| options | object | |
| language | string | Language ID. Required for chatterbox-multilingual. |
| referenceText | string | Optional exact transcript of referenceAudioUrl. Used by f5-tts, voxcpm2, and qwen3-tts-1.7b to skip on-worker Whisper transcription. Omit it if uncertain. Ignored by chatterbox-*. |
| clientRequestId | string | |
| referenceAudioUrl | string | Optional StableUpload URL for a custom voice reference. WAV/MP3/M4A. Required reference duration depends on the model: voxcpm2 and qwen3-tts-1.7b take 3-10s, f5-tts takes 10-15s, chatterbox-* takes 5-15s. |
Output
{
"type": "stablevoice-speech",
"jobId": "cmqki0djh000004lby79bdmte",
"price": "0.02",
"status": "queued"
}Tags
x402
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