API Documentation

Authentication

All API requests require authentication via a Bearer token in the Authorization header.

Authorization: Bearer sk-tts-your-api-key-here

Base URL

All endpoints are relative to this base URL. For example, the TTS endpoint is:

Rate Limits

API rate limits vary by plan:

Rate limit headers are included in every response: X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset.

Credit Costs

Text to Speech

Convert text to speech audio. Returns audio file in the requested format.

Request Body

Example Request

curl -X POST https://api.tts.ai/v1/tts/ \
  -H "Authorization: Bearer sk-tts-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "kokoro",
    "text": "Hello from TTS.ai! This is a test.",
    "voice": "af_bella",
    "format": "mp3"
  }' \
  --output output.mp3

Response

Returns the audio file as binary data with appropriate <code>Content-Type</code> header (<code>audio/mpeg</code>, <code>audio/wav</code>, etc.).

Content-Type: audio/mpeg
Content-Length: 48256
X-Credits-Used: 2
X-Credits-Remaining: 498

Speech to Text

Transcribe audio to text. Supports 99 languages with auto-detection.

Request Body (multipart/form-data)

Response

{
  "text": "Hello, this is a transcription test.",
  "language": "en",
  "duration": 3.5,
  "segments": [
    {
      "start": 0.0,
      "end": 1.8,
      "text": "Hello, this is",
      "speaker": "SPEAKER_00"
    },
    {
      "start": 1.8,
      "end": 3.5,
      "text": "a transcription test.",
      "speaker": "SPEAKER_00"
    }
  ]
}

Voice Cloning

Generate speech in a cloned voice. Upload a reference audio and text.

Request Body (multipart/form-data)

Response

Returns the audio file as binary data, same as the TTS endpoint.

Voice Changer

Convert audio to sound like a different voice. Upload source audio and choose a target voice.

Request Body (multipart/form-data)

Example Request

curl -X POST https://api.tts.ai/v1/voice-convert/ \
  -H "Authorization: Bearer sk-tts-your-key" \
  -F "file=@source_audio.mp3" \
  -F "target_voice=af_bella" \
  -F "model=openvoice" \
  -o converted.wav

Response

Returns the converted audio file as binary data.

Speech Translation

Translate spoken audio from one language to another. Combines speech-to-text, translation, and text-to-speech in a single call.

Request Body (multipart/form-data)

Response

{
  "original_text": "Hello, how are you?",
  "translated_text": "Hola, como estas?",
  "source_language": "en",
  "target_language": "es",
  "audio_url": "https://api.tts.ai/v1/results/translate_abc123.mp3",
  "credits_used": 5
}

Speech to Speech

Transform speech style, emotion, or delivery while keeping the content. Useful for adjusting tone, pacing, and expressiveness.

Request Body (multipart/form-data)

Response

Returns the transformed audio file as binary data.

Audio Tools

Audio processing endpoints for enhancement, vocal removal, stem splitting, and more.

{
  "key": "C",
  "scale": "Major",
  "bpm": 120.0,
  "time_signature": "4/4",
  "camelot": "8B",
  "compatible_keys": ["C Major", "G Major", "F Major", "A Minor"]
}

Voice Chat

Send audio or text and receive an AI response with synthesized speech.

Request Body (multipart/form-data or JSON)

Response

{
  "conversation_id": "conv_abc123",
  "user_text": "What is the capital of France?",
  "ai_text": "The capital of France is Paris.",
  "audio_url": "https://api.tts.ai/v1/audio/tmp/resp_xyz.mp3",
  "credits_used": 3
}

List Models

Returns a list of all available models with their capabilities.

Response

{
  "models": [
    {
      "id": "kokoro",
      "name": "Kokoro",
      "type": "tts",
      "tier": "standard",
      "languages": ["en", "ja", "ko", "zh", "fr"],
      "supports_cloning": false,
      "supports_streaming": true,
      "credits_per_1k_chars": 2
    },
    {
      "id": "chatterbox",
      "name": "Chatterbox",
      "type": "tts",
      "tier": "premium",
      "languages": ["en"],
      "supports_cloning": true,
      "supports_streaming": true,
      "credits_per_1k_chars": 4
    }
  ]
}

List Voices

Returns a list of all available voices, optionally filtered by model or language.

Query Parameters

Response

{
  "voices": [
    {
      "id": "af_bella",
      "name": "Bella",
      "model": "kokoro",
      "language": "en",
      "gender": "female",
      "preview_url": "https://api.tts.ai/v1/voices/preview/af_bella.mp3"
    }
  ],
  "total": 142
}

Code Examples

• Python
• JavaScript
• cURL

import requests

API_KEY = "sk-tts-your-key"

# Text to Speech
response = requests.post(
    "https://api.tts.ai/v1/tts/",
    headers={"Authorization": f"Bearer {API_KEY}"},
    json={
        "model": "kokoro",
        "text": "Hello from TTS.ai!",
        "voice": "af_bella",
        "format": "mp3"
    }
)

with open("output.mp3", "wb") as f:
    f.write(response.content)

print(f"Credits used: {response.headers.get('X-Credits-Used')}")

# Speech to Text
with open("recording.mp3", "rb") as f:
    response = requests.post(
        "https://api.tts.ai/v1/stt/",
        headers={"Authorization": f"Bearer {API_KEY}"},
        files={"file": f},
        data={"model": "faster-whisper", "timestamps": "true"}
    )

result = response.json()
print(result["text"])

# Voice Cloning
with open("reference.wav", "rb") as ref:
    response = requests.post(
        "https://api.tts.ai/v1/tts/clone/",
        headers={"Authorization": f"Bearer {API_KEY}"},
        files={"reference_audio": ref},
        data={
            "text": "This speech uses a cloned voice.",
            "model": "chatterbox"
        }
    )

with open("cloned_output.mp3", "wb") as f:
    f.write(response.content)

const API_KEY = 'sk-tts-your-key';

// Text to Speech
const response = await fetch('https://api.tts.ai/v1/tts/', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${API_KEY}`,
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    model: 'kokoro',
    text: 'Hello from TTS.ai!',
    voice: 'af_bella',
    format: 'mp3'
  })
});

const audioBlob = await response.blob();
const audioUrl = URL.createObjectURL(audioBlob);
const audio = new Audio(audioUrl);
audio.play();

// Speech to Text
const formData = new FormData();
formData.append('file', audioFile);
formData.append('model', 'faster-whisper');

const response = await fetch('https://api.tts.ai/v1/stt/', {
  method: 'POST',
  headers: { 'Authorization': `Bearer ${API_KEY}` },
  body: formData
});

const result = await response.json();
console.log(result.text);

# Text to Speech
curl -X POST https://api.tts.ai/v1/tts/ \
  -H "Authorization: Bearer sk-tts-your-key" \
  -H "Content-Type: application/json" \
  -d '{"model":"kokoro","text":"Hello!","voice":"af_bella","format":"mp3"}' \
  -o output.mp3

# Speech to Text
curl -X POST https://api.tts.ai/v1/stt/ \
  -H "Authorization: Bearer sk-tts-your-key" \
  -F "file=@recording.mp3" \
  -F "model=faster-whisper" \
  -F "timestamps=true"

# Voice Cloning
curl -X POST https://api.tts.ai/v1/tts/clone/ \
  -H "Authorization: Bearer sk-tts-your-key" \
  -F "reference_audio=@reference.wav" \
  -F "text=This uses a cloned voice." \
  -F "model=chatterbox" \
  -o cloned.mp3

# Audio Enhancement
curl -X POST https://api.tts.ai/v1/audio/enhance/ \
  -H "Authorization: Bearer sk-tts-your-key" \
  -F "file=@noisy_audio.mp3" \
  -F "denoise=true" \
  -F "enhance_clarity=true" \
  -o enhanced.mp3

Error Codes

All errors return a JSON response with an error field.

{
  "error": {
    "code": "insufficient_credits",
    "message": "You do not have enough credits for this request.",
    "credits_required": 4,
    "credits_available": 2
  }
}

Webhooks

For long-running tasks (stem splitting, batch TTS), you can provide a <code>webhook_url</code> parameter. When the task completes, we will POST the result to your URL.

{
  "event": "task.completed",
  "task_id": "task_abc123",
  "status": "success",
  "result_url": "https://api.tts.ai/v1/results/task_abc123",
  "credits_used": 12,
  "created_at": "2025-01-15T10:30:00Z",
  "completed_at": "2025-01-15T10:30:45Z"
}