Fingerprinting

Every SessionKit session gets a unique, consistent browser fingerprint that makes it indistinguishable from a real user's browser.

How It Works

When you set fingerprint: 'auto', SessionKit's fingerprint engine:

1. Selects a realistic device profile (OS, screen size, GPU)
2. Generates consistent values for all fingerprinting vectors
3. Applies the fingerprint before any page loads
4. Maintains consistency across navigations within the session

Fingerprint Modes

Auto Mode (Recommended)

const session = await sk.sessions.create({
  fingerprint: 'auto',
})

Generates a random but realistic fingerprint. Best for most use cases.

Custom Fingerprint

Override specific fingerprint values:

const session = await sk.sessions.create({
  fingerprint: {
    platform: 'MacIntel',
    userAgent: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36',
    locale: 'en-US',
    timezone: 'America/New_York',
    viewport: { width: 1440, height: 900 },
    screen: { width: 2560, height: 1600 },
    colorDepth: 30,
    hardwareConcurrency: 10,
    deviceMemory: 16,
    webgl: {
      vendor: 'Apple',
      renderer: 'Apple M1 Pro',
    },
  },
})

Profile-Based Fingerprint

Reuse a fingerprint from a saved profile:

const session = await sk.sessions.create({
  profileId: 'prof_abc123', // Loads fingerprint from profile
  fingerprint: 'profile',  // Explicitly use profile's fingerprint
})

Fingerprint Vectors

SessionKit covers all major fingerprinting vectors:

Vector	What It Does	Consistency
User Agent	Browser + OS identification	Per-session
Platform	navigator.platform value	Per-session
Screen	Resolution and color depth	Per-session
WebGL	GPU vendor/renderer + hash	Per-session
Canvas	2D canvas rendering hash	Per-session
Audio	AudioContext fingerprint	Per-session
Fonts	Installed font detection	Per-session
Plugins	Navigator plugins list	Per-session
Hardware	CPU cores, memory, battery	Per-session
Timezone	Matches proxy geo-location	Per-session

Fingerprint Consistency

Within a session, all fingerprint values remain constant. This means:

• navigator.userAgent returns the same value on every call
• Canvas renders identically every time
• WebGL produces the same hash
• Timezone matches the proxy's geographic location

// These will all return consistent values within a session
await page.evaluate(() => navigator.userAgent)     // Same every time
await page.evaluate(() => navigator.platform)      // Same every time
await page.evaluate(() => navigator.languages)     // Same every time

Anti-Fingerprint Detection

Some sites check for inconsistencies rather than specific values. SessionKit ensures:

• Timezone ↔ Proxy location match (US proxy = US timezone)
• Language ↔ Locale match (en-US locale = English language)
• Screen ↔ Viewport consistency (viewport ≤ screen size)
• GPU ↔ Platform match (Apple GPU only on Mac/iOS)

Warning: Mixing a US residential proxy with a Japanese timezone will trigger detection. Always let auto mode handle consistency, or ensure your custom values are coherent.