@authored/tracker

Privacy-preserving keystroke biometrics tracker for human verification.

Features

• 🔒 Privacy-first: Captures ONLY timing data and key categories, never actual content
• ⚡ Real-time metrics: WPM, pause distribution, error patterns
• 🎯 Biometric data: Dwell times, flight times, digraph/trigraph analysis
• 📦 Zero dependencies: Lightweight (~10KB minified)
• 🌐 Browser-based: Works with any text input or editor

Installation

npm install @authored/tracker

Quick Start

import { KeystrokeTracker } from '@authored/tracker';

const tracker = new KeystrokeTracker({
  // Called when events buffer is full or on interval
  onFlush: async (events) => {
    await fetch('/api/events', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(events)
    });
  },
  
  // Real-time metrics updates
  onMetricsUpdate: (metrics) => {
    console.log('WPM:', metrics.wpm);
    console.log('Backspace ratio:', metrics.backspaceRatio);
  },
  
  // Called when user stops typing
  onIdle: (metrics) => {
    console.log('User idle, final metrics:', metrics);
  }
});

// Start tracking on an element
const editor = document.getElementById('editor');
tracker.start(editor);

// When done
tracker.stop();

API

KeystrokeTracker

Constructor Options

| Option | Type | Default | Description | |--------|------|---------|-------------| | bufferSize | number | 50 | Events to buffer before flush | | flushInterval | number | 5000 | Auto-flush interval in ms | | idleTimeout | number | 3000 | Idle detection timeout in ms | | onFlush | function | - | Callback when events are flushed | | onMetricsUpdate | function | - | Callback for real-time metrics | | onIdle | function | - | Callback when user becomes idle |

Methods

• start(element: HTMLElement) - Start tracking on an element
• stop() - Stop tracking and flush remaining events
• reset() - Reset all tracking data
• flush() - Manually flush buffered events
• forceFlush() - Async flush with completion wait
• getMetrics() - Get current metrics snapshot
• getBiometricData() - Get complete biometric data for ML
• isActive() - Check if tracker is running
• getBufferSize() - Get current buffer size

Types

interface KeystrokeEvent {
  type: 'keydown' | 'keyup' | 'paste';
  timestamp: number;
  keyCategory: KeyCategory;
  flightTime?: number;
  dwellTime?: number;
  // ...
}

interface KeystrokeMetrics {
  totalKeystrokes: number;
  totalBackspaces: number;
  backspaceRatio: number;
  avgDwellTime: number;
  avgFlightTime: number;
  wpm: number;
  pauseDistribution: PauseBuckets;
  errorPatterns: ErrorPatterns;
}

Privacy

This library is designed with privacy as a core principle:

• ✅ Captures timing (dwell time, flight time)
• ✅ Captures key categories (letter, number, space, backspace)
• ❌ Never captures actual characters typed
• ❌ Never captures text content
• ❌ Never stores or transmits readable text

License

MIT License - Copyright (c) 2024-2026 Authored Technologies S.r.l.

Links

• Website: https://authored.tech
• Documentation: https://docs.authored.tech