What is browser fingerprinting?
Most people think deleting cookies stops tracking. It doesn't.
Browser fingerprinting is a highly advanced tracking technique that collects information about your device's configuration. Websites read data points like:
- Screen resolution and colour depth
- Installed fonts and plugins
- Operating system version
- Battery status and hardware concurrency
- Timezone and language settings
When combined, these data points create a unique "fingerprint" that identifies you with high accuracy across the web — even if you use incognito mode or delete your cookies.
Why incognito mode isn't enough
Private browsing only stops your computer from saving your history locally. It does not hide your IP address or your device fingerprint from the websites you visit. To a tracker, your fingerprint looks identical in both normal and private modes.
What does this check actually test?
1. WebRTC leak detection
WebRTC is a browser technology used for video calls and real-time communication. It can sometimes bypass VPNs and reveal your real IP address to websites, even when you think you're protected. This test checks if your LAN or WAN IP is being exposed via STUN servers.
2. Canvas fingerprinting
Scripts can instruct your browser to render a hidden image. Because every graphics card renders things slightly differently, the resulting image data functions like a serial number for your specific device — uniquely identifying you without any cookies.
3. Battery Status API
The HTML5 Battery API was designed to help websites adapt to low-power situations. In practice, the combination of your battery level and charging state creates a temporary unique identifier that trackers can exploit.
4. Tracking protection signals
Do Not Track, Global Privacy Control, and ad blocker presence all affect how aggressively you're being tracked across the web. This check reports what signals your browser is currently sending.
How to improve your browser privacy
- Use a privacy-focused browser: Firefox with
privacy.resistFingerprintingenabled, or Brave, offer strong default protection against fingerprinting. - Install uBlock Origin: The most effective ad and tracker blocker available — also blocks many fingerprinting scripts that cookies alone don't stop.
- Use a VPN: A reputable VPN hides your real IP address and prevents location-based tracking. Make sure it also disables WebRTC in the browser.
- Enable Global Privacy Control: This browser signal tells websites you do not consent to the sale of your data — and is legally binding in some jurisdictions.