--- title: Browser Fingerprinting Explained: How Websites Identify... description: Browser fingerprinting identifies devices by combining small details like screen size, fonts, and GPU rendering quirks, without needing cookies. The EFF's 2010... canonical: https://daily.dev/posts/browser-fingerprinting-explained-how-websites-identify-you-and-how-developers-can-reduce-it-vbwdyej69 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Browser Fingerprinting Explained: How Websites Identify You and How Developers Can Reduce It | daily.dev og:description: Browser fingerprinting identifies devices by combining small details like screen size, fonts, and GPU rendering quirks, without needing cookies. The EFF's 2010... og:url: https://daily.dev/posts/browser-fingerprinting-explained-how-websites-identify-you-and-how-developers-can-reduce-it-vbwdyej69 og:image: https://api.daily.dev/og/posts/vBwdYej69.png og:image:alt: Browser Fingerprinting Explained: How Websites Identify You and How Developers Can Reduce It og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Browser Fingerprinting Explained: How Websites Identify You and How Developers Can Reduce It **[SitePoint](https://daily.dev/sources/sitepoint)** · 10 min read · 2 upvotes · 0 comments ## Summary Browser fingerprinting identifies devices by combining small details like screen size, fonts, and GPU rendering quirks, without needing cookies. The EFF's 2010 Panopticlick study found about 84% of 470,000 tested browsers had a unique fingerprint. Canvas, WebGL, and audio APIs can each be used to generate a stable hash across visits. Chrome, Safari, Firefox, and Brave are each restricting these signals in different ways, and developers can reduce exposure by switching from User-Agent parsing to Client Hints, sandboxing third-party scripts in iframes, applying a strict Content-Security-Policy and Permissions-Policy, and treating stored fingerprints as personal data. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How does canvas fingerprinting work in JavaScript? Canvas fingerprinting draws text and shapes onto a hidden canvas element using the 2D context, then exports it with toDataURL(). Anti-aliasing and subpixel rendering differ slightly across devices and GPUs, so the exported image data varies by hardware even with identical code. Trackers typically hash this output with SHA-256 via the Web Crypto API to produce a short, stable identifier per device. _Developers auditing their own scripts for tracking behavior can find implementation patterns like this on daily.dev._ ### What percentage of browsers have a unique fingerprint according to the EFF Panopticlick study? About 84% of roughly 470,000 tested browsers had a unique fingerprint, according to the EFF's 2010 Panopticlick study. The project continues today under the name Cover Your Tracks. Later studies with larger samples found somewhat lower uniqueness rates, especially on mobile phones, since many phones share near-identical hardware configurations. _Anyone weighing how much fingerprinting really threatens user privacy can track findings like this on daily.dev._ ### How do I replace User-Agent string parsing with Client Hints in a web app? Chromium browsers already send Sec-CH-UA, Sec-CH-UA-Mobile, and Sec-CH-UA-Platform by default, which is enough for most sites. If more detail is genuinely needed, request a specific hint, for example Accept-CH: Sec-CH-UA-Platform-Version, rather than pulling the full User-Agent string. Firefox and Safari don't support Client Hints, so a fallback is required, and feature detection is preferable to browser detection overall. _Teams migrating away from User-Agent sniffing can keep up with Client Hints support across browsers via daily.dev._ ## Similar posts on daily.dev - [Fingerprints Are the New Cookies](https://daily.dev/posts/fingerprints-are-the-new-cookies-fxtqozs0a) · Hacker News · 1 upvotes · 0 comments - [What Your Browser Reveals About You](https://daily.dev/posts/what-your-browser-reveals-about-you-hvayzv86b) · Hacker News · 1 upvotes · 0 comments - [Google Chrome lacks browser fingerprinting defenses](https://daily.dev/posts/google-chrome-lacks-browser-fingerprinting-defenses-f5qvimp5z) · The Register · 3 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#javascript](https://daily.dev/tags/javascript) [View this post on daily.dev](https://daily.dev/posts/browser-fingerprinting-explained-how-websites-identify-you-and-how-developers-can-reduce-it-vbwdyej69) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Browser Fingerprinting Explained: How Websites Identify You and How Developers Can Reduce It","url":"https://daily.dev/posts/browser-fingerprinting-explained-how-websites-identify-you-and-how-developers-can-reduce-it-vbwdyej69","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/browser-fingerprinting-explained-how-websites-identify-you-and-how-developers-can-reduce-it-vbwdyej69"},"datePublished":"2026-10-26T16:32:15.708Z","dateModified":"2026-10-26T16:32:48.949Z","description":"Browser fingerprinting identifies devices by combining small details like screen size, fonts, and GPU rendering quirks, without needing cookies. 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