Tetrax TTS API

The TTS API lets you synthesize lifelike speech from plain text. Send your text, choose a voice preset and output format, and receive a hosted audio URL you can play, embed, or stream anywhere.

Unlike clip-based TTS, there is nothing to pre-record — the neural engine generates natural speech on demand, so every response is unique.

The TTS API uses API key authentication. You must include your trx_tts_* API key in the x-api-key header of every request.

x-api-key: trx_tts_your_key_here

Synthesize your first clip in under a minute. Replace the API key and text with your own values.

curl -X POST https://APIURL.tetrax.in/v1/tts/synthesize \\
  -H "Content-Type: application/json" \\
  -H "x-api-key: trx_tts_your_key" \\
  -d '{
    "text": "Hello! Welcome to TetraX.",
    "voice": "alloy",
    "format": "mp3"
  }'

{
  "success": true,
  "generation_id": "gen_xxx",
  "job": {
    "id": 1,
    "characters": 26,
    "voice": "alloy",
    "format": "mp3",
    "audio_url": "https://APIURL.tetrax.in/v1/tts/audio/s2_1_xxx.mp3",
    "charge": 0.03
  },
  "meta": {
    "characters": 26,
    "charge": 0.03,
    "per_char": 0.001,
    "format": "mp3",
    "audio_url": "https://APIURL.tetrax.in/v1/tts/audio/s2_1_xxx.mp3"
  },
  "model": "tetrax-neural-tts",
  "pricing": { "per_char": 0.001, "minimum_bill": 0.01 }
}

Six natural voice presets are available out of the box. Use the GET /v1/tts/voices endpoint to fetch the live list.

Synthesize Speech

{
  "text": "Hello! Welcome to TetraX.",
  "voice": "alloy",        // optional: default | alloy | echo | fable | onyx | nova | shimmer
  "format": "mp3"          // optional: mp3 | pcm
}

{
  "success": true,
  "generation_id": "gen_xxx",
  "job": {
    "id": 1,
    "characters": 26,
    "voice": "alloy",
    "format": "mp3",
    "audio_url": "https://APIURL.tetrax.in/v1/tts/audio/s2_1_xxx.mp3",
    "charge": 0.03
  },
  "model": "tetrax-neural-tts",
  "pricing": { "per_char": 0.001, "minimum_bill": 0.01 }
}

Request Parameters

Synthesis History

GET /v1/tts/jobs?limit=50

{
  "jobs": [
    {
      "id": 1,
      "text": "Hello! Welcome to TetraX.",
      "characters": 26,
      "voice": "alloy",
      "format": "mp3",
      "audio_url": "https://APIURL.tetrax.in/v1/tts/audio/s2_1_xxx.mp3",
      "status": "completed",
      "charge": 0.03,
      "created_at": "2026-07-23T12:00:00.000Z"
    }
  ],
  "total": 12
}

Analytics

GET /v1/tts/analytics

{
  "summary": {
    "total_syntheses": 12,
    "total_characters": 1240,
    "total_charge": 1.24,
    "avg_chars_per_job": 103
  }
}

List Voice Presets

GET /v1/tts/voices

{
  "voices": [
    { "id": "default", "name": "Default (Natural)", "description": "Balanced, natural-sounding default voice" },
    { "id": "alloy", "name": "Alloy", "description": "Bright and energetic female voice" }
  ]
}

The TTS API uses standard HTTP status codes to indicate success or failure. Error responses include a descriptive message in the response body.

Rate limits protect the API from abuse and ensure fair usage across all customers. Limits are enforced per API key and configured per account (set per account — no monthly fee).

The TTS API uses prepaid wallet billing at ₹0.001/char per character with a ₹0.01 minimum bill per synthesis — no subscriptions, no monthly fees. The charge is deducted from your wallet only after a successful synthesis, and the exact amount is recorded in your wallet transaction history under tts_usage.