What information can a website see about my browser?

Any site you visit can read your User-Agent, screen size, language, timezone, installed fonts, GPU renderer, hardware concurrency, and a long list of device APIs. Combined, these form a fingerprint that often uniquely identifies a browser even without cookies.

Is this data sent to your servers?

No. Every value on this page is read directly in your browser via standard Web APIs and never leaves your device.

How can I reduce what my browser reveals?

Use a privacy-respecting browser (Firefox with resistFingerprinting, Brave, Tor), disable WebGL where you don't need it, install uBlock Origin, and enable Global Privacy Control. A VPN hides your IP but does not hide fingerprint signals.

What is browser fingerprinting?

Fingerprinting is the practice of combining many low-entropy browser signals (timezone, fonts, screen, GPU, audio context) into a single identifier. Because most users have a near-unique combination, sites can track you across visits without cookies.

Does Incognito or Private Browsing hide my fingerprint?

Mostly no. Private modes prevent cookies and history from persisting locally, but the fingerprint signals on this page are identical in normal and private windows.

Privacy

Browser Info Checker

A clear report of everything your browser exposes to the websites you visit.

Reading browser…

What this tool does

The Browser Info Checker enumerates every signal modern browsers expose through standard Web APIs — User-Agent, screen and viewport, language, timezone, GPU renderer, storage availability, network class, and more. It runs entirely client-side, so the report you see is exactly what any website you visit can read about your device.

Why it matters

Individually these values are harmless. Combined, they form a browser fingerprint — a near-unique identifier advertisers, fraud-detection systems, and trackers use to recognise you across sessions even when cookies are blocked.

How to interpret the results

User-Agent — identifies browser, engine, OS, and device family.
Languages & timezone — strong location and locale signals.
Screen, viewport, devicePixelRatio — device-class identification.
GPU renderer — model-specific; one of the highest-entropy signals.
Hardware concurrency & deviceMemory — class of CPU and RAM.
Connection type — wifi, 4g, slow-2g; advertisers gate creatives by this.
Storage flags — whether localStorage / sessionStorage / indexedDB are available.

Common use cases

Verify that a privacy extension hides what it claims to hide.
Reproduce a bug by capturing the exact environment of the user.
Confirm a VPN doesn't change non-network fingerprint signals (it shouldn't).
Audit your stack before depending on a specific Web API.

Limitations

This report shows what your browser exposes via standard APIs. It does not enumerate font lists, canvas hashes, audio-context fingerprints, or WebRTC IP leaks — those are covered in the Privacy Dashboard and VPN leak test. Modern Chrome and Firefox also freeze parts of the User-Agent, so detected browser versions may be capped.

Methodology

Values come from navigator, screen,window, the NetworkInformation API, and a WebGL WEBGL_debug_renderer_info probe. No upstream call, no logging. See the full methodology and data sources.

Related tools & guides

Frequently asked

What information can a website see about my browser?: Any site you visit can read your User-Agent, screen size, language, timezone, installed fonts, GPU renderer, hardware concurrency, and a long list of device APIs. Combined, these form a fingerprint that often uniquely identifies a browser even without cookies.
Is this data sent to your servers?: No. Every value on this page is read directly in your browser via standard Web APIs and never leaves your device.
How can I reduce what my browser reveals?: Use a privacy-respecting browser (Firefox with resistFingerprinting, Brave, Tor), disable WebGL where you don't need it, install uBlock Origin, and enable Global Privacy Control. A VPN hides your IP but does not hide fingerprint signals.
What is browser fingerprinting?: Fingerprinting is the practice of combining many low-entropy browser signals (timezone, fonts, screen, GPU, audio context) into a single identifier. Because most users have a near-unique combination, sites can track you across visits without cookies.
Does Incognito or Private Browsing hide my fingerprint?: Mostly no. Private modes prevent cookies and history from persisting locally, but the fingerprint signals on this page are identical in normal and private windows.