RunLocalTools

Browser Fingerprint Checker: See What Your Browser Reveals, Offline

See your browser fingerprint: 30 signals including canvas, WebGL, fonts and audio, with spoofing checks and a privacy exposure score. Save snapshots and compare browsers. Nothing leaves your device.

Slug: browser-fingerprint-check

What it does

Websites can recognise your browser without cookies by combining many small details: your screen, fonts, graphics card, language settings and how your browser draws and computes things. This tool reads those details in your own tab, shows you each one, and turns them into a single fingerprint hash you can compare over time.

It also checks whether your browser’s answers agree with each other. A user agent that says “Windows” while the platform says “Mac”, or a graphics card that cannot exist on your operating system, usually means something is spoofing values, and the tool tells you.

How it works

The checker runs about 30 readings, each isolated so that one blocked feature never stops the rest:

  • Identity: user agent, Client Hints, platform, languages, CPU cores, memory, plugins, privacy flags.
  • Screen and locale: resolution, pixel ratio, display preferences, timezone, calendar and number formatting.
  • Graphics and audio: a hidden canvas drawing, WebGL renderer details, a WebGL test scene, WebGPU adapter info and an audio-processing test.
  • Fonts and system: which of about 150 common fonts are installed, plus emoji and glyph metrics.
  • Media and devices: codec support, device counts, speech voices, permission states, available APIs and keyboard layout.
  • Engine and integrity: JavaScript engine behaviour, and a comparison of what a background worker and an iframe report against the page itself.

Three techniques make the results more than a list of values:

  • Stability test. Canvas, WebGL and audio are each read twice. If the same drawing gives different results, your browser or an extension is adding noise. Noisy signals are marked “randomised” and left out of your stable fingerprint, because a tracker cannot rely on them.
  • Consistency checks. Over a dozen rules compare signals with each other: user agent against platform and Client Hints, timezone name against clock offset, GPU against operating system, native functions against JavaScript replacements, and the page against a worker and iframe.
  • Hashing. Each signal and the combined stable set are hashed with SHA-256, so two fingerprints can be compared without reading every value.

How to use it

  1. Open the page. The scan runs automatically and takes a few seconds.
  2. Read the exposure score and the findings first. Anything marked “Inconsistent” is worth a closer look.
  3. Open any signal card to see the raw value, what it is, how trackers use it and how to reduce it.
  4. Press Save to store a snapshot of this browser’s fingerprint.
  5. Open the tool again in a private window, another browser or with a VPN on, and press Compare to see which signals changed.
  6. Download the report as JSON, text or HTML. To compare with another device, import its JSON report.

Reading the results

Inconsistent or worth a look

These come from the consistency checks. They point to values that do not fit together, which is what spoofing extensions tend to produce. Browsers with built-in protection, such as Brave, Firefox and Tor Browser, patch values natively, so they are not flagged as replaced functions.

Randomised

Your browser is adding noise to that reading, so it differs each time it is read. That defeats a tracker that relies on the value, though it can also make you look unusual among people who do not use such protection.

The exposure score

The score is a rough estimate. Each signal has a fixed weight for how much detail it usually reveals, reduced when the signal is randomised. It is not a measurement against real browser populations, so treat it as a comparison between your own settings, not as odds of being unique.

Limits

  • The tool makes no network requests, so it cannot show your public IP address or location, and it does not run WebRTC leak tests that need an outside server. The WebRTC reading only shows local addresses gathered without contacting anything.
  • Some readings depend on the browser. Firefox and Safari do not expose Client Hints or keyboard layout, and iframes can restrict permissions and WebGPU. Unavailable readings are labelled instead of guessed.
  • Real fingerprinting also uses your IP address, HTTP headers and behaviour over time, which a page cannot observe here.

Privacy

Nothing is uploaded and no requests are sent. Snapshots you save are stored in this browser only and can be cleared with one button. Reports you download contain your fingerprint values, so share them carefully. If you want to look at other data your browser stores about you, the cookie and localStorage inspector shows it, and the user-agent parser breaks down the user agent string in more detail. Photos carry their own hidden data, which Bare can show and remove.

FAQ

Is my fingerprint unique?

Possibly, especially with a common desktop browser and default settings. Fingerprinting works by combining many details, and each one narrows the crowd. This tool cannot check against a database of other visitors, so it estimates exposure instead of claiming a “1 in a million” figure.

Does private or incognito mode change it?

Mostly not. Private windows clear cookies and history, but your screen, fonts, GPU and language settings stay the same. Save a snapshot in a normal window, then compare in a private window to see for yourself.

Why was my browser flagged as inconsistent?

Usually an extension or setting is changing one value without the others: a user-agent switcher, a timezone changer or a script-injecting privacy add-on. Read the finding text, which names exactly which values disagree.

What does “randomised” mean, and should I worry?

It means the browser adds small random changes to canvas, WebGL or audio output so trackers cannot use it as a stable ID. That is usually a good sign. The trade-off is that it can make you stand out from users with no protection.

How can I lower my exposure?

Each signal card lists options for that reading. In general: use a browser with built-in fingerprint protection, keep window sizes and fonts common, avoid rare browser extensions, and check the result again after any change.

Why can’t it show my IP address?

Finding your public IP requires asking an outside server, and this tool is built to stay fully local. For the same reason it does not include a DNS or WebRTC public-address leak test.