GitHub - Lorenzo-Coslado/fingerprinter-js: Lightweight JavaScript library (with full TypeScript support) for generating unique browser fingerprints — ideal for device identification, analytics, and fraud prevention.

npm install fingerprinter-js

import Fingerprint from "fingerprinter-js";

// Simple generation
const result = await Fingerprint.generate();
console.log(result.fingerprint); // "a1b2c3d4e5f6..."
console.log(result.confidence); // 85

import { Fingerprint } from "fingerprinter-js";

// With custom options
const fingerprint = new Fingerprint({
  excludeCanvas: true,
  excludeWebGL: true,
  customData: {
    userId: "12345",
    sessionId: "abc-def-ghi", // ⚠️ Will be automatically filtered for stability
    version: "1.0", // ✅ Stable, will be kept
  },
});

// To include unstable data (not recommended)
const unstableFingerprint = new Fingerprint({
  allowUnstableData: true,
  customData: {
    timestamp: Date.now(), // ⚠️ Will make fingerprint unstable
    sessionId: "random-id",
  },
});

const result = await fingerprint.generate();

// Enable bot/fraud detection
const result = await Fingerprint.generate({
  includeSuspectAnalysis: true,
});

console.log(result.suspectAnalysis);
// {
//   score: 15,           // 0-100 (0=legitimate, 100=very suspicious)
//   riskLevel: 'LOW',    // LOW/MEDIUM/HIGH
//   signals: [...],      // Detected suspicious signals
//   details: {...}       // Analysis details
// }

interface FingerprintOptions {
  excludeScreenResolution?: boolean;
  excludeTimezone?: boolean;
  excludeLanguage?: boolean;
  excludeCanvas?: boolean;
  excludeWebGL?: boolean;
  excludeAudio?: boolean;
  excludePlugins?: boolean;
  excludeFonts?: boolean;
  customData?: Record<string, any>;
  allowUnstableData?: boolean; // Allow temporal data (default: false)
  includeSuspectAnalysis?: boolean; // Include suspect analysis (default: false)
}

const fingerprint = new Fingerprint();
const components = await fingerprint.getComponents();

console.log(components);
// {
//   userAgent: "Mozilla/5.0...",
//   language: ["en-US", "en"],
//   timezone: "America/New_York",
//   screen: { width: 1920, height: 1080, ... },
//   canvas: "data:image/png;base64,...",
//   webgl: { vendor: "Google Inc.", ... },
//   ...
// }

const result = await Fingerprint.generate({
  includeSuspectAnalysis: true,
});

if (result.suspectAnalysis.score > 70) {
  // Block or challenge suspicious users
  console.log("Suspicious activity detected");
  console.log("Signals:", result.suspectAnalysis.signals);
} else if (result.suspectAnalysis.score > 30) {
  // Require additional authentication
  console.log("Moderate risk detected");
} else {
  // Allow normal access
  console.log("Legitimate user");
}

const fp = new Fingerprint({
  customData: {
    // ✅ Kept (stable)
    version: "1.0",
    theme: "dark",

    // ❌ Automatically filtered (unstable)
    timestamp: Date.now(),
    sessionId: "123e4567-e89b-12d3-a456-426614174000",
    random: Math.random(),
  },
});

// Result: only version and theme will be included

const fp = new Fingerprint({
  allowUnstableData: true, // ⚠️ Disables filtering
  customData: {
    timestamp: Date.now(), // Will make fingerprint unstable
  },
});

import { Fingerprint, CanvasCollector, WebGLCollector } from "fingerprinter-js";

// Use only specific collectors
const canvas = new CanvasCollector();
const canvasData = await canvas.collect();

const webgl = new WebGLCollector();
const webglData = await webgl.collect();

interface FingerprintResult {
  fingerprint: string; // Fingerprint hash
  components: Record<string, any>; // Collected data
  confidence: number; // Confidence level (0-100)
  suspectAnalysis?: SuspectAnalysis; // Optional suspect analysis
}

interface SuspectAnalysis {
  score: number; // Suspect score (0-100)
  riskLevel: "LOW" | "MEDIUM" | "HIGH";
  signals: SuspectSignal[];
  details: Record<string, any>;
}

const result = await Fingerprint.generate({ includeSuspectAnalysis: true });
if (result.suspectAnalysis.score > 80) {
  // Block transaction
}

const result = await Fingerprint.generate({ includeSuspectAnalysis: true });
const automationSignals = result.suspectAnalysis.signals.filter((s) =>
  ["webdriver", "headless", "selenium"].includes(s.type)
);
if (automationSignals.length > 0) {
  // Challenge with CAPTCHA
}

const result = await Fingerprint.generate({ includeSuspectAnalysis: true });
if (result.suspectAnalysis.score < 40) {
  // Include in analytics
  track("page_view", { fingerprint: result.fingerprint });
}