Audio Fingerprinting: How the Web Audio API Tracks Your Device
Audio Fingerprinting: How the Web Audio API Tracks Your Device
What Is Audio Fingerprinting?
Audio fingerprinting is a browser tracking technique that generates a unique identifier from the way your device processes audio signals. It uses the Web Audio API — a legitimate browser feature designed for music applications, games, and audio effects — to create a short audio signal, process it through your device's audio stack, and measure the resulting output. Because different hardware and software configurations process audio slightly differently, the output is unique to your device. For the strategic overview of where audio fingerprinting fits in the broader picture, see our complete browser fingerprinting guide.
Like canvas and WebGL fingerprinting, audio fingerprinting requires no storage on your device and is unaffected by cookie deletion, private browsing mode, or VPN usage.
How Audio Fingerprinting Works
The audio fingerprinting process involves creating an AudioContext object in JavaScript, generating a test oscillator signal, applying audio processing, and measuring the resulting waveform values. These values differ between devices based on the audio hardware, operating system audio drivers, and system settings.
Protection Against Audio Fingerprinting
Brave browser randomizes AudioContext output to prevent audio fingerprinting. Firefox with privacy.resistFingerprinting enabled reports modified audio values. The CanvasBlocker extension for Firefox provides additional audio fingerprint blocking options.
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