What is Font Fingerprinting?
Think of your computer's fonts like your wardrobe. Most people have common shirts (like Arial or Times New Roman). But maybe you installed a special design program or a language pack that added rare "clothes" to your closet. Font Fingerprinting is when a website takes a look at your entire "closet" to see what you own. Because your combination of fonts is unique, it’s a very easy way to recognize you every time you visit.
How do they do it secretly?
Websites don't need your permission to see your fonts. They use a trick called Introspection. They try to draw a piece of text using a font name. If the text width changes, they know you have that font. AirOI Checker runs this same test to show you exactly what they see.
Why does this matter for your privacy?
Even if you use a VPN or Incognito mode, your fonts stay the same. This means:
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Cross-site Tracking: Advertisers can follow you from a news site to a shopping site because your font list matches.
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Persistent Identity: You can't "clear" your fonts like you clear cookies. As long as those fonts are on your computer, your ID is active.
Frequently Asked Questions
How can I stop websites from seeing my fonts?
The best way is to use the Brave Browser or Firefox. Brave adds "noise" to the results, making your fonts look different every time. Firefox has a special "Resist Fingerprinting" mode that only shows a few standard fonts.
Does having more fonts make me more trackable?
Yes. If you have 200 fonts installed, you are much easier to identify than someone who only has the standard 20 fonts that come with Windows or Mac.
Is this tool free for everyone?
Yes! AirOI Checker provides this privacy check for free so you can see if your browser is protecting you or leaking your data.