Browser Fingerprint Tester

Browser fingerprinting is a tracking technique that identifies users by collecting characteristics of their browser and device — screen resolution, installed fonts, WebGL renderer, canvas rendering, timezone, language, and dozens more. Unlike cookies, fingerprints cannot be deleted because they are derived from your system configuration. Studies show that 83-99% of browsers have a unique fingerprint, making it a powerful tracking method that works even in private/incognito mode.

Cookies are small text files stored on your device that you can view, delete, or block. Browser fingerprinting collects system attributes that exist regardless of cookie settings — your GPU, screen size, timezone, installed fonts, audio context, and more. Cookies require consent under GDPR; fingerprinting often happens without user knowledge. Fingerprints persist across sessions and incognito mode because they rely on hardware and software characteristics, not stored data.

Reducing fingerprint uniqueness is possible but difficult. Browser extensions like uBlock Origin and Privacy Badger block some fingerprinting scripts. Firefox has Enhanced Tracking Protection with fingerprinting resistance. Tor Browser standardizes many attributes across users. Using common screen resolutions, default fonts, and disabling WebGL reduces uniqueness. However, the most effective approach is using privacy-focused analytics like Zenovay that do not use fingerprinting at all.

The GDPR and ePrivacy Directive treat browser fingerprinting as personal data processing when it can identify an individual (which it almost always can). Article 5(3) of the ePrivacy Directive requires informed consent for storing or accessing information on a user's device, which courts have interpreted to include fingerprinting. The French CNIL and Austrian DSB have both ruled that fingerprinting without consent violates EU law.

Canvas fingerprinting draws invisible text and shapes on an HTML5 canvas element, then reads the pixel data. Different GPUs, drivers, operating systems, and font rendering engines produce subtly different pixel values for the same drawing instructions. This creates a nearly unique identifier. Canvas fingerprinting is the most common fingerprinting technique, used by over 5% of the top 100,000 websites according to research by Princeton University.

Entropy measures how much identifying information a fingerprinting attribute carries, measured in bits. One bit of entropy halves the candidate pool. For example, if 50% of users have a specific timezone, it carries ~1 bit of entropy. Screen resolution might carry 4-5 bits (1 in 16-32 users share yours). Combined, 20+ bits of entropy from multiple attributes can uniquely identify a browser among millions. Higher total entropy means a more unique (and trackable) fingerprint.