Browser fingerprinting bypasses traditional cookie-based tracking by aggregating technical device parameters into a unique hash. Tracking scripts query the Web Audio API, WebGL, and WebGPU to extract hardware-specific rendering differences. Because GPU drivers and operating systems render images and audio signals with minute variations, these outputs create a stable identifier that persists through incognito mode and history clears.

Technical implementations include canvas fingerprinting, where hidden images are drawn to detect pixel-level rendering differences, and font enumeration to identify installed system software. While ad tech firms use these identifiers for behavioral profiling, security platforms employ them for fraud prevention and bot detection by flagging login attempts from unrecognized device profiles.

Protection requires altering the browser's reported signals. Brave Browser randomizes signals per session, while Tor Browser and Mullvad Browser standardize all outputs so users appear identical. Notably, VPNs only mask IP addresses and do not prevent fingerprinting. Over-installing privacy extensions can paradoxically increase uniqueness, as specific extension combinations create a distinct behavioral signature.