capacitor-gemini-nano

A Capacitor plugin for on-device AI using Gemini Nano via Google's ML Kit GenAI Prompt API.

Features

• On-device AI: Run Gemini Nano locally on supported Android devices
• No API keys required: Completely free and unlimited
• Offline capable: Works without internet connection
• Privacy-first: All processing stays on device

Supported Devices

Gemini Nano is available on:

• Google Pixel 9, Pixel 9 Pro, Pixel 9 Pro XL, Pixel 9 Pro Fold
• Samsung Galaxy S24 series (with One UI 6.1+)
• Samsung Galaxy S25 series
• Other devices with Android AICore support

Installation

npm install capacitor-gemini-nano
npx cap sync

Requirements

• Capacitor 8.0+
• Android minSdkVersion 26+
• Device with Gemini Nano support
• AICore app installed and updated

Usage

Check Status

import { GeminiNano } from 'capacitor-gemini-nano';

const status = await GeminiNano.checkStatus();
console.log(status);
// { status: 'available' | 'downloadable' | 'downloading' | 'unavailable', message: string }

Download Model (if needed)

// Listen for download progress
GeminiNano.addListener('onDownloadProgress', (data) => {
  console.log(`Download progress: ${data.progress}%`);
});

const result = await GeminiNano.downloadModel();
if (result.success) {
  console.log('Model downloaded!');
}

Generate Text

// Warm up the model (optional but recommended)
await GeminiNano.warmup();

// Generate response
const result = await GeminiNano.generate({
  prompt: 'What is the capital of France?',
  temperature: 0.7,
  maxOutputTokens: 256
});

if (result.success) {
  console.log(result.text);
}

Streaming Generation

GeminiNano.addListener('onToken', (data) => {
  process.stdout.write(data.token);
});

GeminiNano.addListener('onComplete', (data) => {
  console.log('\nComplete:', data.fullText);
});

GeminiNano.addListener('onError', (data) => {
  console.error('Error:', data.error);
});

await GeminiNano.generateStream({
  prompt: 'Write a short poem about coding',
  temperature: 0.8
});

API

Methods

| Method | Description | |--------|-------------| | checkStatus() | Check if Gemini Nano is available | | downloadModel() | Download the model if status is 'downloadable' | | warmup() | Pre-warm the model for faster first generation | | generate(options) | Generate text (non-streaming) | | generateStream(options) | Generate text with streaming |

GenerateOptions

| Property | Type | Default | Description | |----------|------|---------|-------------| | prompt | string | required | The input prompt | | temperature | number | 0.7 | Creativity (0.0-1.0) | | topK | number | 40 | Top-K sampling | | maxOutputTokens | number | 256 | Maximum output length |

Events

| Event | Data | Description | |-------|------|-------------| | onDownloadProgress | { progress: number } | Download progress (0-100) | | onToken | { token: string } | Streaming token | | onComplete | { fullText: string } | Streaming complete | | onError | { error: string } | Error occurred |

Limitations

• Output tokens: ~256 tokens max per generation
• Context window: ~3000 words input
• Android only: iOS not supported (no Gemini Nano on iOS)
• Device dependent: Only works on supported hardware

Troubleshooting

"Gemini Nano unavailable"

1. Check if your device is supported
2. Update Google Play Services
3. Update AICore app (Settings > Apps > AICore)
4. Change device region to US (some regions restricted)
5. Join the Android AICore beta program

"Model needs download"

Call downloadModel() and wait for completion. This requires WiFi and can take several minutes.

License

MIT

Credits

Built with ML Kit GenAI Prompt API.