Your browser is identifiable even when you clear cookies. The mechanism is called browser fingerprinting, and it works because every device renders content a little differently.
Where the differences come from
- Canvas. A page draws text or shapes to a hidden
<canvas>, reads the pixels back, and hashes them. Font rendering, anti-aliasing, and GPU settings vary per device, so the hash varies too. - WebGL. The same canvas trick with 3D rendering exposes the GPU vendor and renderer string, which is highly device-specific.
- Audio. The
AudioContextAPI processes a signal slightly differently per hardware and driver stack, producing a measurable "audio fingerprint." - Fonts. The set of installed fonts a browser reports is unique enough to be a strong signal on its own.
Why local tools don't need it
Fingerprinting is a tracking technique — it exists to identify you across sites. A local tool has no reason to fingerprint anything. When a tool runs entirely in your browser, it can do its job with just the input you give it.
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That is why this site ships fingerprint detectors rather than collectors: Canvas Fingerprint Detector, Audio Context Fingerprint Detector, Font Fingerprint Detector, WebGL Fingerprint Detector, and WebGPU Fingerprint Detector. Run them to see how much of your device is exposed to any page you visit.
What to do with the result
Seeing a fingerprint is not a reason to panic. It is a reason to be deliberate: block third-party scripts on sites that have no business tracking you, use a browser with strong fingerprint resistance if it matters to you, and remember that the most effective protection is simply not loading code you don't trust.
