Browser fingerprint test

What a browser fingerprint is

A browser fingerprint is an identifier worked out from the characteristics your browser and device reveal when you visit a website. None of them identifies you on its own, but the combination of dozens of values is usually rare enough to tell your browser apart from almost every other one.

Unlike a cookie, a fingerprint is not stored on your device: it is recomputed on every visit. That is why it does not show up in the site data list and does not go away when you clear your history.

Which signals make your browser unique

These are the most common signals. The more of them are combined, the easier it is to tell one browser from another.

Canvas

The site asks the browser to draw some text or a shape and reads back the pixels. The graphics card, the operating system and font smoothing make the result differ slightly from one device to the next.

Fonts

Installed fonts depend on your operating system and the software you have, such as Office or Adobe. They can be detected by measuring how a piece of text is drawn.

Screen

The resolution, the space left without the taskbar, the pixel density and the colour depth.

GPU

Through WebGL, the browser can reveal the make and model of the graphics card and how it renders a 3D scene.

Time zone

Your system's time zone and the date and time format it uses.

Languages

The list of preferred languages the browser sends to every site, and their order.

TLS

Before the page loads, the browser negotiates the secure connection. The order of ciphers and extensions in that TLS hello (summarised in fingerprints such as JA3 or JA4) gives away which browser and version is behind it, even without JavaScript.

Why clearing cookies or going incognito does not change it

Private or incognito mode only stops the browser from keeping the history, cookies and form data once you close the window. The screen, graphics card, fonts, time zone and languages stay the same, so the resulting fingerprint is usually identical.

Some browsers do change something in private windows: Safari adds advanced fingerprinting protection and Brave adds small random variations per site and per session. If you see a different ID in a private window, your browser is one of them.

What it is used for: stopping fraud, and also tracking

Banks, shops and sites like this one use fingerprints to stop fraud: spotting bots that send thousands of requests, warning about a sign-in from a new device, or stopping one person from opening hundreds of accounts. On NoCall, ByteGuard uses it so that reports and comments about phone numbers come from people, not from automated programs.

The same technique can be used to follow you from one site to another for advertising, without cookies and without you noticing. In the European Union, the ePrivacy rules treat that access to your device's information like cookies: tracking for advertising needs your consent.

The ID you see here is tied to NoCall: ByteGuard derives it with a key specific to each site, so another site protected by ByteGuard would see a different ID for the same browser.

How to reduce your fingerprint

You cannot remove it completely, but you can make your browser look more like everyone else's:

• Tor Browser makes all its users present the same screen, fonts and settings, so the fingerprint no longer singles you out.
• Brave adds random variations to canvas, audio and other signals, different on every site.
• In Firefox, the privacy.resistFingerprinting setting (in about:config) sets the time zone to UTC, rounds the window size and evens out other signals; its tracking protection also blocks known fingerprinting scripts.
• Install few extensions: each one can add details that make you stand out.
• Keep the browser up to date and avoid very unusual settings: looking like most people is what protects you.

Frequently asked questions