Can I be fingerprinted in private browsing mode?

Private browsing (incognito mode) prevents your browser from storing cookies, history, and form data locally. It does not change the signals your browser sends — screen resolution, fonts, WebGL renderer, canvas output, and other fingerprinting vectors remain identical. Private browsing protects you from other users of the same device, not from websites tracking you.

How accurate is browser fingerprinting?

In a 2020 study, researchers achieved 99.2% unique identification accuracy across browsers using a comprehensive fingerprint. Modern fingerprinting-resistant browsers like Tor and Brave have reduced this, but identification rates above 80% remain common for browsers that do not implement resistance measures.

Does a VPN prevent fingerprinting?

No. A VPN masks your IP address but does not change your browser fingerprint. The signals that create your fingerprint — screen resolution, fonts, WebGL, canvas rendering, audio context — are all transmitted in the HTTP request headers and JavaScript-accessible APIs regardless of whether you use a VPN.

What is canvas fingerprinting?

Canvas fingerprinting uses the HTML5 canvas element to render text or graphics, then extracts the rendered pixels as a unique identifier. Different browsers, GPUs, and operating systems produce different pixel outputs for identical drawing commands. The resulting image hash is unique enough to identify most users.

Browser Fingerprinting: The Invisible Trail You Leave Behind

Every browser leaves a unique fingerprint — a combination of screen resolution, installed fonts, WebGL renderer, and dozens of other signals that identify you without cookies. Here is how it works, what it reveals, and how to reduce your exposure.

When you visit a website, your browser transmits more than the page URL. It transmits a collection of signals — screen resolution, installed fonts, WebGL renderer, canvas output, audio processing, timezone, language preferences — that together form a unique identifier. This identifier is your browser fingerprint, and it is being collected by thousands of websites right now. Unlike cookies, browser fingerprints require no storage, no consent, and no opt-in. Unlike tracking scripts, fingerprints cannot be deleted because there is nothing to delete. The fingerprint is created from the information your browser already transmits as part of normal operation. How Fingerprinting Works A browser fingerprint is a collection of signals that, together, uniquely identify a browser instance. The most commonly collected signals include: Hardware signals: Screen resolution, pixel ratio, GPU renderer (exposed through WebGL), number of CPU cores, and device memory. These vary by hardware and driver version. Software signals: Installed fonts (queried through CSS font enumeration), browser extensions (detected through API availability), user agent string, and operating system version. These vary by software configuration. Behavioral signals: Timezone, preferred language, cookie settings, and JavaScript engine version. These vary by locale and configuration. No single signal uniquely identifies you. The power comes from combining signals. A user running Chrome on macOS with a Retina display, three specific fonts, and the Adblock Plus extension produces a fingerprint that is statistically unique. The process works like this: a website loads JavaScript that queries available APIs (screen dimensions, navigator properties, canvas output), combines the results into a hash, and sends that hash to a tracking server. The hash is not stored as a cookie — it is generated fresh from your browser's characteristics on every visit. Clear your cookies, and the fingerprint remains. Why Fingerprinting Is Difficult to Prevent Fingerprinting is difficult to prevent because the signals it collects are the same signals websites need to render correctly. Screen resolution affects layout. Font availability affects typography. WebGL renderer affects graphics. Blocking these signals would break the web. The exception is browsers that implement fingerprinting resistance by making all users look identical. Tor Browser achieves this by running in a single window size, standardizing the font list, and spoofing the WebGL renderer. The result is that every Tor Browser user produces the same fingerprint. Brave achieves a similar effect by randomizing certain signals. For most users, the question is not whether they can achieve perfect anonymity but whether their browsing is distinguishable from a generic profile. A user who installs a few common extensions and uses standard settings produces a fingerprint that blends in with thousands of other users. The fingerprint becomes unique when unusual configurations — rare fonts, unusual screen sizes, specific extension combinations — create a signal that stands out. The Fingerprinting Ecosystem The commercial fingerprinting ecosystem is mature. Companies like FingerprintJS (which explicitly offers browser identification), and data brokers collect and store fingerprints. The technology has moved beyond academic research into a standard tracking mechanism. A typical fingerprinting script on a major website collects 20 to 30 signals in under 100 milliseconds. The signals are sent to a tracking server, which checks them against a database of known fingerprints. If a match is found, the visit is linked to the user's previous browsing. If no match is found, a new profile is created. The business model is straightforward: cross-site tracking without cookies. Advertisers use fingerprints to track users across websites, measure ad effectiveness, and build interest profiles. The same technology is used by fraud detection systems to identify suspicious behavior, by analytics platforms to count unique visitors, and by governments to identify activists and journalists. What You Can Do The practical steps for reducing fingerprint exposure depend on your threat model: For general privacy: Use a browser with fingerprint resistance (Brave, Mullvad, or Tor Browser for high-risk browsing). Disable JavaScript on sites you do not trust. Avoid uncommon browser configurations that create unique fingerprints. For high-risk browsing: Use Tor Browser in its default configuration. Do not resize the window, install extensions, or change settings. The goal is to look like every other Tor Browser user. For testing: Use our Browser Fingerprint Checker to see what your browser reveals. Check the canvas, WebGL, and audio fingerprints — these are the most unique signals. Fingerprinting is one of the most pervasive and least understood forms of tracking on the web. Unlike cookies, you cannot opt out. Unlike tracking scripts, you cannot delete. The only defense is to understand what your browser reveals and choose tools that minimize the signal.