> ## Documentation Index
> Fetch the complete documentation index at: https://smallestai-ff1e543d.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Lightning TTS API — generate speech from text with 80+ voices, 44.1 kHz audio, ~100ms latency, and streaming support.

The Lightning TTS API converts text into natural speech via `https://api.smallest.ai/waves/v1`. 80+ voices across 4 languages, 44.1 kHz native sample rate, \~100ms latency, with sync, SSE, and WebSocket streaming.

**Hear Lightning v3.1 (voice: magnus):**

<video controls style={{ width: '100%', maxWidth: '500px', height: '54px' }}>
  <source src="https://mintcdn.com/smallestai-ff1e543d/__rdeLT6wbSp7Z7Q/audio/tts-sample-hello.wav?fit=max&auto=format&n=__rdeLT6wbSp7Z7Q&q=85&s=bdb0210e6e55870d289dd5709b56e062" type="audio/wav" data-path="audio/tts-sample-hello.wav" />
</video>

<Card title="Quickstart" icon="rocket" href="/v4.0.0/content/text-to-speech/quickstart">
  Generate your first audio in under 60 seconds.
</Card>

## Synthesis Modes

Choose the synthesis mode that best fits your application's needs:

<CardGroup cols={2}>
  <Card title="Synchronous" icon="file-audio" href="/v4.0.0/content/text-to-speech/how-to-tts">
    Generate complete audio files with a single HTTP request. Ideal for pre-rendering content, batch processing, and applications where immediate streaming isn't required.
  </Card>

  <Card title="Streaming" icon="broadcast-tower" href="/v4.0.0/content/text-to-speech/stream-tts">
    Receive audio chunks as they're generated via WebSocket. Perfect for real-time voice assistants, live narration, and low-latency conversational AI.
  </Card>
</CardGroup>

## Available Models

<CardGroup cols={2}>
  <Card title="Lightning v2" icon="bolt">
    <Badge color="orange">Legacy</Badge> High-quality multilingual TTS with 100ms TTFB. Supports 16+ languages including English, Hindi, and European languages. Includes voice cloning support.
  </Card>

  <Card title="Lightning v3.1" icon="sparkles">
    Our most natural-sounding model with 44 kHz audio output. Ultra-low latency with expressive, human-like speech. Supports English, Hindi, Tamil, and Spanish with voice cloning.
  </Card>
</CardGroup>

## Feature Highlights

<AccordionGroup>
  <Accordion title="Ultra-Low Latency">
    Optimized streaming pipeline delivers sub-100ms time-to-first-byte (TTFB) for real-time applications. Lightning v3.1 achieves even faster response times for conversational AI.
  </Accordion>

  <Accordion title="Voice Cloning">
    Create custom voice profiles by uploading audio samples. Instant voice cloning works with just a few seconds of audio, while professional voice cloning delivers studio-quality results.
  </Accordion>

  <Accordion title="16+ Languages">
    Comprehensive language support including English, Hindi, Tamil, Kannada, Malayalam, Telugu, Gujarati, Bengali, Marathi, German, French, Spanish, Italian, Polish, Dutch, and Russian.
  </Accordion>

  <Accordion title="Multiple Output Formats">
    Choose from PCM, WAV, MP3, or μ-law encoding. Configurable sample rates from 8kHz to 44kHz to match your application's requirements.
  </Accordion>

  <Accordion title="Speed Control">
    Adjust speech rate with a simple multiplier. Slow down for clarity or speed up for faster content delivery without pitch distortion.
  </Accordion>

  <Accordion title="Pronunciation Dictionaries">
    Define custom pronunciations for brand names, technical terms, and acronyms. Ensure consistent, accurate pronunciation across all synthesized audio.
  </Accordion>

  <Accordion title="High-Quality Audio">
    Lightning v3.1 produces 44 kHz audio with natural prosody and expressiveness. Perfect for audiobooks, podcasts, and premium voice experiences.
  </Accordion>

  <Accordion title="WebSocket Streaming">
    Persistent connections for continuous audio streaming. Ideal for voice bots and interactive applications where latency is critical.
  </Accordion>
</AccordionGroup>

## Supported Languages

<table style={{ borderCollapse: 'separate', borderSpacing: 0, width: '100%', borderRadius: '8px', overflow: 'hidden' }}>
  <thead>
    <tr style={{ backgroundColor: 'rgba(255, 255, 255, 0.08)' }}>
      <th style={{ padding: '12px 16px', textAlign: 'left', fontWeight: '800', border: '0.5px solid rgba(209, 213, 219, 0.2)', borderTopLeftRadius: '8px' }}>Language</th>
      <th style={{ padding: '12px 16px', textAlign: 'left', fontWeight: '800', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Code</th>
      <th style={{ padding: '12px 16px', textAlign: 'left', fontWeight: '800', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Lightning v2</th>
      <th style={{ padding: '12px 16px', textAlign: 'left', fontWeight: '800', border: '0.5px solid rgba(209, 213, 219, 0.2)', borderTopRightRadius: '8px' }}>Lightning v3.1</th>
    </tr>
  </thead>

  <tbody>
    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>English</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>en</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Hindi</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>hi</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Tamil</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>ta</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Kannada</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>kn</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Malayalam</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>ml</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Telugu</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>te</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Gujarati</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>gu</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Bengali</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>bn</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Marathi</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>mr</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>German</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>de</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>French</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>fr</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Spanish</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>es</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Italian</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>it</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Polish</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>pl</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Dutch</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>nl</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>—</td>
    </tr>

    <tr>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)', borderBottomLeftRadius: '8px' }}>Russian</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}><code>ru</code></td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)' }}>Yes</td>
      <td style={{ padding: '12px 16px', border: '0.5px solid rgba(209, 213, 219, 0.2)', borderBottomRightRadius: '8px' }}>—</td>
    </tr>
  </tbody>
</table>

## Explore

<CardGroup cols={3}>
  <Card title="Quickstart" icon="rocket" href="/v4.0.0/content/text-to-speech/quickstart">
    First API call in 60 seconds
  </Card>

  <Card title="Streaming" icon="broadcast-tower" href="/v4.0.0/content/text-to-speech/stream-tts">
    Real-time audio via WebSocket
  </Card>

  <Card title="Voice Cloning" icon="microphone" href="/v4.0.0/content/voice-cloning/how-to-vc-ui">
    Clone from 5-15 seconds of audio
  </Card>

  <Card title="Cookbook" icon="book" href="https://github.com/smallest-inc/cookbook/tree/main/text-to-speech">
    20+ open-source examples on GitHub
  </Card>

  <Card title="Showcase" icon="grid-2" href="https://showcase.smallest.ai/">
    See what developers have built
  </Card>

  <Card title="Model Card" icon="id-card" href="/v4.0.0/content/text-to-speech/model-cards/lightning-v3-1">
    Lightning v3.1 specs and benchmarks
  </Card>
</CardGroup>