What Is Browser Fingerprinting?
Every time you visit a website, your browser silently shares dozens of details about your device, software, and settings. Combined, these details create a unique identifier — your browser fingerprint — that can track you across the web without ever storing a cookie on your machine.
How Browser Fingerprinting Works
When your browser loads a webpage, it automatically sends information through HTTP headers: your User-Agent string, accepted languages, encoding preferences, and more. JavaScript on the page can then query dozens of additional properties — screen resolution, installed fonts, WebGL renderer, audio processing characteristics, timezone, and hardware specs.
Individually, each piece of data is shared by millions of people. But the combination of all these signals is often unique. Research by the Electronic Frontier Foundation found that browser fingerprints can uniquely identify over 90% of browsers.
How many data points does your browser leak?
Browser Inspector detects 80+ signals that any website can collect — without asking permission. Try it now →
What Data Gets Collected
Network & Location
IP address, approximate city, ISP, connection type, VPN detection
Browser & Engine
Name, version, rendering engine, user agent, client hints, language preferences
Device & Hardware
Operating system, CPU cores, device memory, architecture, touch support
Screen & Display
Resolution, pixel density, color depth, dark mode, HDR support, orientation
Graphics & Media
WebGL renderer, GPU vendor, canvas rendering, audio fingerprint, codecs
Privacy & Security
Do Not Track, incognito detection, ad blocker status, tracker blocking
Who Uses Browser Fingerprinting?
- •Advertising networks use it to track users across sites without cookies, especially as third-party cookies are phased out.
- •Fraud prevention systems use it to detect bots, account takeovers, and payment fraud.
- •Analytics platforms use it as a fallback identifier when cookies are blocked.
- •Content protection services use it to enforce paywalls and licensing restrictions.
How to Protect Yourself
- 1Use a privacy-focused browser — Firefox and Brave both include built-in fingerprint resistance that randomizes or blocks certain signals.
- 2Install an ad blocker — uBlock Origin blocks fingerprinting scripts before they can run. It also blocks trackers and ads.
- 3Use a VPN — A VPN masks your IP address, removing the most visible tracking signal.
- 4Enable Global Privacy Control — GPC signals websites to opt you out of data selling. Supported by major browsers.
- 5Keep your browser updated — New browser versions add privacy protections and patch known fingerprinting techniques.
- 6Reduce unique extensions — Each browser extension can subtly alter page behavior in detectable ways.
- 7Audit your fingerprint — Use Browser Inspector to see exactly what your browser exposes and verify your protections work.
Want to see how well your protections are working? Run Browser Inspector →
More Tools
Full Browser Inspector
See all 80+ data points your browser exposes
What Is My IP?
Check your public IP, location, and ISP
What Is My Browser?
Detect your browser, version, OS, and device type
IPv6 Leak Test
Check whether your IPv6 address leaks alongside your VPN's IPv4
WebRTC Leak Test
Detect local and public IPs exposed by WebRTC, even behind a VPN
DNS Leak Test
See which resolver answers your queries and whether it bypasses your VPN
JavaScript Information
Inspect your JS engine, supported features, and runtime capabilities
Canvas Fingerprint
See the unique image your browser renders and how trackers use it
Geolocation API Test
Check what coordinates your browser exposes via the Geolocation API
TLS Client Test
Inspect your ClientHello, cipher suites, and JA3 fingerprint
Incognito / Private Mode Test
Detect whether your browser is in Incognito or Private Browsing mode