What Is Browser Fingerprinting?
Browser fingerprinting is a tracking technique that identifies and re-identifies users based on the unique combination of attributes reported by their browser and device - Without using cookies. When dozens of individually common attributes are combined, the resulting fingerprint is statistically unique enough to track individuals across websites and sessions - Even across a VPN or IP change. Check your own fingerprint with our browser fingerprint tool.
Data Points Used in Browser Fingerprints
| Attribute | How It's Collected | Uniqueness Contribution |
|---|---|---|
| User-Agent string | HTTP header sent automatically | Medium |
| Screen resolution & color depth | JavaScript: screen.width, screen.colorDepth | Medium |
| Installed fonts | Canvas rendering or CSS font-face tests | High |
| Canvas fingerprint | Render a hidden canvas; GPU & driver produce unique pixel output | Very High |
| WebGL renderer info | JavaScript: WebGL RENDERER and VENDOR strings | High |
| Audio context fingerprint | Render a silent audio signal; floating-point differences are unique | High |
| Timezone & language | JavaScript: Intl.DateTimeFormat, navigator.language | Low–Medium |
| Browser plugins | navigator.plugins list | Medium (less now due to deprecation) |
| TCP/IP fingerprint | OS-level network stack timing and TTL values | Medium |
| Battery status | Battery API (deprecated in most browsers) | Low |
How to Reduce Your Fingerprint
- Use Firefox with the Resist Fingerprinting setting enabled (privacy.resistFingerprinting = true in about:config) - It normalizes most attributes.
- Use the Tor Browser - It is purpose-built to make all users look identical.
- Install uBlock Origin - It blocks many fingerprinting scripts before they execute.
- Avoid installing unusual fonts or browser extensions - Each one makes your fingerprint more unique.
- Use a VPN to mask your IP, but understand that fingerprinting works without it - Both protections are complementary. Verify your VPN isn't leaking with our VPN leak test.
Fingerprinting vs Cookies
Unlike cookies, fingerprinting leaves nothing on your device, cannot be cleared, and works in private browsing mode. It is harder to detect and harder to block because it uses legitimate browser APIs. The most effective protection is browser-level normalization that makes your browser look like everyone else's, rather than blocking individual tracking attempts. WebRTC is another browser API that can leak your real IP even through a VPN.