What information can a website collect about me without permission?

Without a prompt, a website can commonly see your IP address, approximate city, browser and device type, screen size, language, timezone, and available graphics signals. Browser support and privacy settings limit battery, memory, font, media-device, and fingerprinting inputs. This page shows which signals your browser exposes.

What is a browser fingerprint?

A browser fingerprint combines characteristics such as screen size, fonts, GPU, and timezone into a potentially identifying pattern. The Electronic Frontier Foundation's historical Panopticlick research measured about 18 bits of identifying information in the browsers it tested; modern results vary by browser and privacy defenses.

Can a website see my exact location?

By default a site only sees your approximate city, derived from your IP address. Pinpoint GPS location — accurate to a few metres — requires your explicit permission, but many apps and sites request it as a matter of routine.

Can websites see my other tabs or which sites I'm logged into?

No. The browser sandbox and same-origin policy stop any page from reading your other tabs, your history, or another site's data. However, a page can still detect the moment you switch away from its tab, the site you arrived from, and — sometimes — which major services still recognise your browser session.

How do I stop websites from tracking me?

Install a content blocker such as uBlock Origin, use a privacy-focused browser (Brave, Firefox, or Tor), deny camera, microphone, location, and clipboard access by default, block third-party cookies, and turn on Global Privacy Control. Together these steps cut off the large majority of trackers.

Does this website store any of my data?

It stores no raw test readings or server-side visitor profile. The returning-visitor demo keeps one fingerprint hash and visit count in your browser's localStorage. The reveal also makes disclosed third-party requests for IP geolocation and tracker checks. Cookieless analytics does not load when DNT or GPC is enabled.

Can canvas fingerprinting identify me by itself?

Usually not. It is one signal in a larger browser fingerprint, and its usefulness depends on how distinctive and stable the rendering result is alongside other available signals.

Is canvas fingerprinting the same as a cookie?

No. A cookie stores an identifier in the browser, while canvas fingerprinting computes a signal from rendering behavior. A site can use either one, or combine them, to recognize a returning browser.

Canvas Fingerprinting Explained: How Websites Recognize Your Browser

Canvas fingerprinting asks your browser to render a controlled image, then treats the resulting pixels as one clue about the browser and device. It is a component of a broader fingerprint, not a magic identity lookup.

Published August 18, 2026 · 5 min read

What the canvas API does

The canvas API lets a page create a bitmap and draw text, shapes, colors, and images into it. It is a normal web feature used for graphics, games, charts, and image editing; using it is not automatically suspicious.

How pixel differences become a signal

A fingerprinting script can draw the same content on different devices and read the pixels back. Font rendering, graphics drivers, operating-system text smoothing, and the browser's implementation can produce small differences. The script hashes or otherwise summarizes those pixels and combines that result with other signals.

What canvas fingerprinting can and cannot prove

A canvas result can help distinguish browsers, especially when combined with screen, language, timezone, fonts, and graphics signals. By itself it does not reveal your name, prove that one person is using the device, or remain identical forever. Browser updates, settings, privacy defenses, and a different device can change the result.

How a safe self-test works

A self-test can draw a non-sensitive local image, read its pixels, and show a summary without uploading the raw image or fingerprint. Check the page's privacy statement before running any third-party test, and do not grant unrelated permissions just to test canvas rendering.

How to reduce canvas tracking

Privacy browsers may standardize, randomize, or block canvas reads. Blocking third-party scripts can reduce who gets to run fingerprinting code, while a common browser configuration can make your device less distinctive. Each defense has compatibility and anonymity trade-offs; no single setting removes every tracking method.

Frequently asked questions

Can canvas fingerprinting identify me by itself?: Usually not. It is one signal in a larger browser fingerprint, and its usefulness depends on how distinctive and stable the rendering result is alongside other available signals.
Is canvas fingerprinting the same as a cookie?: No. A cookie stores an identifier in the browser, while canvas fingerprinting computes a signal from rendering behavior. A site can use either one, or combine them, to recognize a returning browser.

Sources & further reading

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