Fingerprint WASM

Fingerprint WASM is an open-source, client-side, browser fingerprinting library written in Rust and compiled to WebAssembly. It is a Rust + WASM port of the popular FingerprintJS library.

This library queries browser attributes and computes a hashed visitor identifier from them. Unlike cookies and local storage, a fingerprint stays the same in incognito/private mode and even when browser data is purged.

Why WebAssembly?

Unlike pure JavaScript implementations, Fingerprint WASM compiles all core fingerprinting logic into WebAssembly:

• Enhanced Security: Core fingerprinting algorithms are compiled to WASM binary, making them significantly harder to reverse engineer, tamper with, or spoof compared to plain JavaScript
• Code Protection: The WASM binary obfuscates the fingerprinting logic, providing an additional layer of protection against malicious actors
• Tamper Resistant: Modifying WASM bytecode is far more difficult than modifying JavaScript source code

Features

• Secure Core: All fingerprinting logic runs in WebAssembly, not JavaScript
• Comprehensive Fingerprinting: Collects 40+ browser entropy sources
• TypeScript Support: Full TypeScript type definitions included
• Framework Agnostic: Works with any JavaScript framework or vanilla JS
• Small Bundle Size: Optimized WASM output

Demo

Clone the repository and run the playground:

git clone https://github.com/Steven-Qiang/fingerprint-wasm.git
cd fingerprint-wasm
pnpm install
pnpm build:wasm
cd playground
pnpm dev

Then open http://localhost:5173 in your browser to see your visitor identifier.

Installation

NPM

npm install fingerprint-wasm
# or
pnpm add fingerprint-wasm
# or
yarn add fingerprint-wasm

CDN

<script type="module">
  import init, { getFingerprint } from 'https://unpkg.com/fingerprint-wasm/dist/fingerprint_wasm.js';
  
  async function main() {
    await init();
    const result = await getFingerprint();
    console.log('Visitor ID:', result.visitorId);
  }
  
  main();
</script>

Usage

Basic Usage

import init, { getFingerprint } from 'fingerprint-wasm';

async function getVisitorId() {
  // Initialize the WASM module
  await init();
  
  // Get the fingerprint
  const result = await getFingerprint();
  
  console.log('Visitor ID:', result.visitorId);
  console.log('Confidence:', result.confidence);
  console.log('Components:', result.componentsJson);
  
  return result.visitorId;
}

getVisitorId();

With Vue.js

<script setup>
import { ref, onMounted } from 'vue';
import init, { getFingerprint } from 'fingerprint-wasm';

const visitorId = ref('');
const isLoading = ref(true);
const confidence = ref(null);

onMounted(async () => {
  await init();
  const result = await getFingerprint();
  visitorId.value = result.visitorId;
  confidence.value = result.confidence;
  isLoading.value = false;
});
</script>

<template>
  <div v-if="isLoading">Loading...</div>
  <div v-else>
    <p>Visitor ID: {{ visitorId }}</p>
    <p>Confidence: {{ confidence?.score }}</p>
  </div>
</template>

With React

import { useEffect, useState } from 'react';
import init, { getFingerprint } from 'fingerprint-wasm';

function App() {
  const [visitorId, setVisitorId] = useState('');
  const [confidence, setConfidence] = useState(null);
  const [isLoading, setIsLoading] = useState(true);

  useEffect(() => {
    async function loadFingerprint() {
      await init();
      const result = await getFingerprint();
      setVisitorId(result.visitorId);
      setConfidence(result.confidence);
      setIsLoading(false);
    }
    loadFingerprint();
  }, []);

  if (isLoading) return <div>Loading...</div>;
  return (
    <div>
      <p>Visitor ID: {visitorId}</p>
      <p>Confidence: {confidence?.score}</p>
    </div>
  );
}

export default App;

API Reference

init()

Initializes the WebAssembly module. Must be called before using getFingerprint().

import init from 'fingerprint-wasm';

await init();

getFingerprint(options?: FingerprintOptions): Promise<FingerprintResult>

Returns a promise that resolves to a FingerprintResult object containing the visitor identifier and related data.

Parameters

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | options | FingerprintOptions | No | Optional configuration for fingerprinting |

FingerprintOptions

| Property | Type | Description | |----------|------|-------------| | debug | boolean | Enable debug mode for detailed logging |

Returns

| Property | Type | Description | |----------|------|-------------| | visitorId | string | The unique visitor identifier | | confidence | ConfidenceResult | Confidence score and comment | | componentsJson | string | JSON string of all entropy components | | version | string | Library version |

ConfidenceResult

| Property | Type | Description | |----------|------|-------------| | score | number | Confidence score (0-1) | | comment | string \| undefined | Optional comment about the confidence |

Entropy Sources

The library collects the following entropy sources to generate the fingerprint:

| Source | Description | |--------|-------------| | architecture | CPU architecture | | audio | Audio context fingerprint | | audioBaseLatency | Audio context base latency | | applePay | Apple Pay availability | | canvas | Canvas 2D fingerprint | | colorDepth | Screen color depth | | colorGamut | Color gamut support | | contrast | Contrast preference | | cookiesEnabled | Cookies enabled status | | cpuClass | CPU class (legacy) | | dateTimeLocale | Date/time locale | | deviceMemory | Device memory | | domBlockers | Ad blocker detection | | fonts | Available fonts | | fontPreferences | Font preferences | | forcedColors | Forced colors mode | | hardwareConcurrency | CPU cores | | hdr | HDR support | | indexedDB | IndexedDB availability | | invertedColors | Inverted colors mode | | languages | Browser languages | | localStorage | Local storage availability | | math | Math precision fingerprint | | monochrome | Monochrome display | | openDatabase | WebSQL availability | | osCpu | OS CPU info | | pdfViewerEnabled | PDF viewer status | | platform | Browser platform | | plugins | Browser plugins | | privateClickMeasurement | Private click measurement | | reducedMotion | Reduced motion preference | | reducedTransparency | Reduced transparency | | screenFrame | Screen frame dimensions | | screenResolution | Screen resolution | | sessionStorage | Session storage availability | | timezone | Timezone | | touchSupport | Touch support | | vendor | Browser vendor | | vendorFlavors | Browser vendor flavors | | webGlBasics | WebGL basic info | | webGlExtensions | WebGL extensions |

Building from Source

Prerequisites

• Rust (1.70+)
• wasm-pack
• Node.js (18+)
• pnpm (recommended)

Build Steps

# Clone the repository
git clone https://github.com/Steven-Qiang/fingerprint-wasm.git
cd fingerprint-wasm

# Install dependencies
pnpm install

# Build the WASM module
pnpm build:wasm

# For optimized production build
pnpm build:wasm:optimized

# Run tests
pnpm test

Testing

The project includes comprehensive Playwright tests for browser compatibility:

# Run all tests
cd tests
pnpm test

# Run tests for specific browser
pnpm test -- --project="Desktop Chrome"
pnpm test -- --project="Desktop Firefox"
pnpm test -- --project="Desktop Safari"

# Run tests for mobile devices
pnpm test -- --project="iPhone 14"
pnpm test -- --project="Pixel 7"

Project Structure

fingerprint-wasm/
├── wasm/                   # Core Rust/WASM source code
│   ├── src/
│   │   ├── sources/        # Entropy source implementations
│   │   ├── utils/          # Utility functions
│   │   ├── agent.rs        # Main fingerprint agent
│   │   ├── confidence.rs   # Confidence calculation
│   │   └── lib.rs          # WASM bindings
│   └── Cargo.toml
├── playground/             # Vue.js demo application
├── tests/                  # Playwright browser compatibility tests
├── dist/                   # Compiled WASM output
└── package.json

All core fingerprinting logic resides in the wasm/ directory and is compiled to WebAssembly for enhanced security.

Limitations

Accuracy

Since Fingerprint WASM processes and generates fingerprints from within the browser itself, the accuracy is limited compared to commercial solutions that use server-side processing.

Security Considerations

While WASM provides better code protection than JavaScript, no client-side solution is completely secure. Determined attackers may still find ways to analyze or bypass fingerprinting. For mission-critical applications, consider using a commercial solution with server-side processing.

Browser Support

The library supports all modern browsers with WebAssembly support:

| Browser | Minimum Version | |---------|----------------| | Chrome | 57+ | | Firefox | 52+ | | Safari | 11+ | | Edge | 16+ | | Opera | 44+ | | iOS Safari | 11+ | | Chrome Android | 57+ |

Contributing

We welcome contributions! Please see our Contributing Guide for details.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

This project is a Rust + WebAssembly port of FingerprintJS. Special thanks to the FingerprintJS team for their excellent work on browser fingerprinting.

Related Projects

• FingerprintJS - Original JavaScript library
• Fingerprint Pro - Commercial version with higher accuracy and server-side processing