> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/XDcobra/react-native-sherpa-onnx/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Overview of react-native-sherpa-onnx - offline and streaming speech processing for React Native

# Introduction to react-native-sherpa-onnx

A React Native TurboModule that provides **offline and streaming speech processing** capabilities using [sherpa-onnx](https://github.com/k2-fsa/sherpa-onnx). Process speech entirely on-device with no internet connection required.

## What is react-native-sherpa-onnx?

react-native-sherpa-onnx brings powerful speech processing capabilities to React Native applications:

* **Speech-to-Text (STT)** - Convert audio to text offline
* **Text-to-Speech (TTS)** - Generate natural-sounding speech from text
* **Streaming Recognition** - Real-time speech recognition with partial results
* **Streaming TTS** - Low-latency incremental speech generation
* **100% Offline** - All processing happens on-device with no internet required

## Key Features

### Offline Speech-to-Text

Transcribe audio files or samples without an internet connection. Supports multiple model architectures:

* **Zipformer/Transducer** - Balanced speed and accuracy
* **Whisper** - Multilingual, zero-shot capabilities
* **Paraformer** - Fast non-autoregressive ASR
* **NeMo CTC** - Excellent for English and streaming
* **SenseVoice** - Emotion and punctuation detection
* **Moonshine** - Lightweight streaming-capable models
* And many more (see [Supported Models](#supported-models))

### Online (Streaming) Speech-to-Text

Real-time recognition from microphone or audio streams:

* Partial results as the user speaks
* Endpoint detection for natural pauses
* Low latency for responsive UX
* Use streaming-capable models (transducer, paraformer, nemo\_ctc, tone\_ctc)

### Text-to-Speech

Generate high-quality speech from text:

* **VITS** - Fast, high-quality (Piper, Coqui, MeloTTS)
* **Matcha** - High-quality acoustic model with vocoder
* **Kokoro** - Multi-speaker, multi-language
* **KittenTTS** - Lightweight multi-speaker
* **Zipvoice** - Voice cloning support

### Streaming Text-to-Speech

Incremental speech generation for low time-to-first-byte:

* Start playback while generating
* Ideal for long texts
* Chunk-based callbacks for streaming audio

### Hardware Acceleration

Optimize performance with execution providers:

* **Android**: CPU, NNAPI, XNNPACK, QNN (Qualcomm)
* **iOS**: CPU, Core ML, Apple Neural Engine
* Automatic detection and support checking

### Flexible Model Loading

* **Asset models** - Bundle models in your app
* **File system models** - Download and use external models
* **Play Asset Delivery (PAD)** - Android on-demand model delivery
* **Automatic detection** - Auto-detect model types

### Developer Experience

<CardGroup cols={2}>
  <Card title="TypeScript Support" icon="code">
    Full type definitions for all APIs
  </Card>

  <Card title="Instance-Based API" icon="cube">
    Multiple STT/TTS engines in parallel
  </Card>

  <Card title="Model Quantization" icon="compress">
    Automatic int8 model detection
  </Card>

  <Card title="Cross-Platform" icon="mobile">
    iOS and Android production ready
  </Card>
</CardGroup>

## Supported Models

### Speech-to-Text Models

| Model Type           | Use Case                | Streaming Support |
| -------------------- | ----------------------- | ----------------- |
| Zipformer/Transducer | Balanced speed/accuracy | ✅ Yes             |
| Whisper              | Multilingual, zero-shot | ❌ Offline only    |
| Paraformer           | Fast inference          | ✅ Yes             |
| NeMo CTC             | English, streaming      | ✅ Yes             |
| SenseVoice           | Emotion detection       | ❌ Offline only    |
| Moonshine            | Lightweight streaming   | ✅ Yes             |
| Tone CTC (t-one)     | Lightweight CTC         | ✅ Yes             |

See the complete list in [Model Types](/models/stt/overview).

### Text-to-Speech Models

| Model Type | Description                                |
| ---------- | ------------------------------------------ |
| VITS       | Fast, high-quality (Piper, Coqui, MeloTTS) |
| Matcha     | Acoustic model + vocoder                   |
| Kokoro     | Multi-speaker, multi-language              |
| KittenTTS  | Lightweight multi-speaker                  |
| Zipvoice   | Voice cloning with encoder/decoder         |
| Pocket     | Flow-matching TTS                          |

## Platform Support

| Platform    | Status             | Notes                  |
| ----------- | ------------------ | ---------------------- |
| **Android** | ✅ Production Ready | API 24+ (Android 7.0+) |
| **iOS**     | ✅ Production Ready | iOS 13.0+              |

## Requirements

* **React Native** >= 0.70
* **Android** API 24+ (Android 7.0+)
* **iOS** 13.0+
* **@dr.pogodin/react-native-fs** (peer dependency for file operations)

## Architecture

react-native-sherpa-onnx uses React Native TurboModules for high-performance native integration:

```
┌─────────────────────────────────────┐
│   React Native JavaScript Layer     │
│  (TypeScript API + Type Safety)     │
└──────────────┬──────────────────────┘
               │ TurboModule Bridge
┌──────────────▼──────────────────────┐
│      Native Module (Obj-C/Kotlin)   │
│   Instance Management + Threading   │
└──────────────┬──────────────────────┘
               │ C++ API
┌──────────────▼──────────────────────┐
│         sherpa-onnx (C++)           │
│    ONNX Runtime + Model Inference   │
└─────────────────────────────────────┘
```

## Why Choose react-native-sherpa-onnx?

<AccordionGroup>
  <Accordion title="Privacy & Offline Capability">
    All processing happens on-device. No data leaves the user's phone, and no internet connection is required. Perfect for privacy-sensitive applications.
  </Accordion>

  <Accordion title="Cost Effective">
    No API calls, no per-request costs, no rate limits. Once the model is bundled or downloaded, transcription and synthesis are completely free.
  </Accordion>

  <Accordion title="Low Latency">
    Direct on-device processing means no network round-trips. Streaming STT provides partial results in real-time, and streaming TTS can start playback within milliseconds.
  </Accordion>

  <Accordion title="Production Ready">
    Battle-tested in production apps with CI/CD automation, comprehensive documentation, and active maintenance.
  </Accordion>
</AccordionGroup>

## Example Use Cases

* **Voice assistants** - Offline voice commands and responses
* **Transcription apps** - Convert meetings, lectures, or interviews to text
* **Accessibility tools** - Text-to-speech for visually impaired users
* **Language learning** - Real-time pronunciation feedback
* **Voice notes** - Convert voice memos to searchable text
* **Healthcare apps** - Medical transcription with privacy compliance
* **Navigation apps** - Turn-by-turn voice guidance

## What's Next?

<CardGroup cols={2}>
  <Card title="Installation" icon="download" href="/installation">
    Install the library and set up iOS/Android
  </Card>

  <Card title="Quick Start" icon="rocket" href="/quickstart">
    Get up and running with your first example
  </Card>

  <Card title="STT Guide" icon="microphone" href="/features/speech-to-text">
    Learn about speech-to-text features
  </Card>

  <Card title="TTS Guide" icon="volume-high" href="/features/text-to-speech">
    Explore text-to-speech capabilities
  </Card>
</CardGroup>

<Note>
  **Breaking changes in v0.3.0**: If you're upgrading from 0.2.x, see the [Migration Guide](/resources/migration) for important API changes.
</Note>