Thumb.js – Lightweight Browser Fingerprint Library

Thumb.js is a powerful yet lightweight browser fingerprinting library that generates unique, high-entropy device signatures based on a wide array of browser and hardware characteristics. Perfect for enhancing security, preventing fraud, or implementing robust user identification systems without relying on cookies or local storage.

✨ Features

• Forever FREE & Unlimited - No dependency, no server cost, runs on regular browser.
• High Entropy Fingerprinting - Combines 18+ device and browser characteristics
• Cryptographically Secure - Uses SHA-256 hashing for maximum uniqueness
• Lightweight - Zero dependencies, only 2KB minified
• Easy to Implement - Simple API with promise-based fingerprint generation
• Cross-Browser Compatible - Works in all modern browsers
• Privacy-Focused - All processing happens client-side; no data is transmitted

📦 Installation

NPM

npm install thumb-browser

Yarn

yarn add thumb-browser

Direct Script Include

<script src="https://unpkg.com/thumb-browser@latest/dist/thumb.min.js"></script>

🚀 Quick Start

import Thumb from 'thumb-browser';

// Create a new fingerprinter instance
const fingerprinter = new Thumb();

// Generate a fingerprint
fingerprinter.get()
    .then(fingerprint => {
        console.log('Your device fingerprint:', fingerprint);
        // e.g. "3f4e591c86c9c5f734fc4b54d5322549bf85ec34b4c2f36310490b3e187b733d"
    })
    .catch(error => {
        console.error('Error generating fingerprint:', error);
    });

🔍 How It Works

Thumb.js collects and combines multiple sources of entropy to create a unique, stable fingerprint:

1. User Agent & Browser Data

   • Browser user agent string
   • Language settings
   • Do Not Track preferences

2. Hardware & System Information

   • Screen resolution and color depth
   • Device memory & CPU core count
   • Touch point capability
   • Timezone information
   • Window dimensions

3. Advanced Graphical Fingerprinting

   • Canvas rendering characteristics
   • WebGL vendor and renderer details
   • Color gamut capabilities

4. Audio Processing

   • Audio context behavior (unique to hardware)

5. Additional Signal Sources

   • Installed plugins
   • Battery status
   • Network connection type
   • Random entropy enhancer

All data points are combined and processed through SHA-256 to generate a consistent, high-entropy fingerprint that balances uniqueness with stability across sessions.

📊 API Reference

new Thumb()

Creates a new Thumb.js instance.

async get()

Generates and returns the fingerprint.

• Returns: Promise<string> - The SHA-256 fingerprint hash.

async collect()

Collects all data points used for fingerprinting.

• Note: This is called automatically by the get() method.

Other Methods

Several specialized methods collect individual components for fingerprinting:

• getCanvas() - Canvas-based rendering fingerprint
• getAudio() - Audio processing fingerprint
• getWebGL() - WebGL vendor and renderer info
• getPlugins() - Browser plugins enumeration
• getColorGamut() - Screen color capabilities
• getBattery() - Battery level detection
• getNetwork() - Network connection information
• getNoise() - Random entropy addition

🔐 Security Considerations

• Thumb.js is designed for legitimate security purposes like fraud prevention and risk analysis
• Always disclose fingerprinting usage to your users in your privacy policy
• Consider offering opt-out options in compliance with privacy regulations
• The fingerprint is intentionally designed to be stable but not perfectly permanent to balance security with privacy

👩‍💻 Use Cases

• Fraud Prevention: Detect suspicious activities across different sessions
• Enhanced Authentication: Add an extra security layer to login systems
• Bot Detection: Identify automated browsing behavior
• Secure Transactions: Add verification without additional user friction
• Cross-Device Recognition: Improve user experience without requiring login

⚙️ Advanced Customization

You can extend the Thumb class to add additional sources of entropy or modify existing collection methods:

import Thumb from 'thumb-browser';

class EnhancedThumb extends Thumb {
  async collect() {
    // Call the original collection method
    await super.collect();

    // Add custom entropy sources
    this.data.push(this.getCustomData());
  }

  getCustomData() {
    // Your custom fingerprinting logic here
    return 'custom-entropy-value';
  }
}

📝 License

MIT License - feel free to use and modify as needed.

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Developed by Jafran Hasan, Sr Software Developer at WPPOOL.