Browser Fingerprinting on MacBook (Safari)

Browser Fingerprinting on MacBook (Safari)

Apple's rule requiring every iOS browser app to run on WebKit does not reach macOS.¹ Chrome and Firefox installed on this MacBook run their own Blink and Gecko engines rather than wrapping Safari's WebKit the way every browser on an iPhone must, so the browser you pick here genuinely changes which engine renders the page and which anti-fingerprinting behavior, if any, applies to it. This machine also lets you install custom fonts system-wide through Font Book, something the fixed factory font set on a phone rarely sees.

Specifications

Why the browser you pick on this Mac changes more than it does on an iPhone

Apple's App Store Review Guidelines require apps that browse the web on iOS to use the WebKit rendering engine, a rule numbered 2.5.6.¹ That requirement governs iOS App Store distribution specifically; it has no equivalent for macOS. Chrome and Firefox installed on this MacBook ship their native Blink and Gecko engines rather than wrapping WebKit, which means picking a browser here is a genuinely different decision than picking one on a phone, where every app icon leads back to the same underlying engine.

Safari's protections are Safari-specific on this machine

Safari on macOS offers an "Advanced Tracking and Fingerprinting Protection" toggle in Safari > Settings > Advanced, which layers noise and normalization onto canvas, WebGL, and audio readouts when enabled.² That protection lives inside WebKit itself, so it only ever covers browsing sessions that actually run through Safari on this machine. Opening the same page in Chrome on this identical MacBook leaves you on Blink with none of it, a fundamentally different situation from an iPhone where every browser app inherits the same engine-level defenses automatically.

A fresh Chrome profile on this Mac starts from a genuinely different baseline

Because Chrome and Safari on this MacBook run different rendering engines rather than the same engine wrapped in different interfaces, a script comparing canvas hashes between the two would see output shaped by two distinct rendering pipelines, not just two different browser UIs sitting on identical internals. That is a deeper split than Samsung Internet versus Chrome on the same Galaxy phone, where CapyToolkit's own Android guide shows both browsers query identical hardware signal APIs even though their canvas hashes differ; here, switching browsers can mean switching engines outright.

Why the font list on this Mac can grow well past a phone's fixed set

Font Book lets you install fonts system-wide on this MacBook, either for your own account or for every user on the machine.³ Font enumeration, one of the techniques browser fingerprinting relies on, reads from the operating system's installed font list rather than anything scoped to a single browser, so anything added through Font Book becomes visible to a probe running in Safari, Chrome, or Firefox alike on this same machine.

An installed font library becomes a shared fingerprinting signal across every browser here

Installing a design agency's licensed typefaces or a Creative Cloud font library through Font Book adds entries a canvas-based font probe can detect in any browser you open afterward, since the detection happens at the OS level rather than inside a sandboxed per-app font set.⁴ A phone's fixed, rarely-customized factory font set gives a fingerprinting script much less to work with by comparison; a MacBook whose owner has installed a personal or professional font library over the years hands over a list that reflects real software choices, not just the operating system's defaults.

That distinction compounds with the browser-engine point above: a script running on this MacBook can potentially see a distinctive font list through whichever browser you're using, then combine it with an engine-specific canvas or WebGL signature that a phone, locked to one shared engine across every app, simply cannot produce in the same way.⁵