What Is Browser Fingerprinting?
Browser fingerprinting is a tracking technique that identifies you based on your browser and device characteristics — without using cookies. It collects data like:
- Browser type and version
- Operating system
- Screen resolution
- Installed fonts
- WebGL renderer (your graphics card)
- Audio context
- Canvas rendering
- Timezone and language
- Installed plugins
Combined, these create a unique "fingerprint" that identifies you with 90-99% accuracy.
How Is It Different from Cookies?
| Feature | Cookies | Fingerprinting |
|---|---|---|
| Storage | Stored in browser | Not stored — calculated each visit |
| Can be deleted | Yes | No — it's based on your hardware |
| Can be blocked | Yes, easily | Harder to block |
| User consent required | Yes (GDPR) | Often done without consent |
| Accuracy | High (unique ID) | Very high (90-99%) |
Who Uses Fingerprinting?
- Ad companies: To track you when cookies are blocked
- Fraud prevention: Banks use it to detect unusual logins
- Analytics: Some analytics services use it as a cookie alternative
What Changed: Google Now Permits It
When this technique first got attention, it was something the ad industry did quietly and platforms officially frowned on. Google's own 2019 position was that fingerprinting "subverts user choice and is wrong".
That position is gone. From 16 February 2025, Google dropped the prohibition on advertisers using device fingerprinting in its advertising products (the UK Information Commissioner's Office responded critically, noting that people cannot meaningfully consent to or control fingerprinting the way they can with cookies).
The other half of the picture: Privacy Sandbox was retired in October 2025, ending the six-year attempt to build a replacement for third-party cookies, and those cookies now stay in Chrome indefinitely.
So the situation is not the one most explainers describe. Cookies did not go away, the sanctioned replacement never arrived, and the technique that was supposed to be the disreputable fallback is now permitted by the largest ad platform. Fingerprinting is not a fringe method any more.
Why that makes it harder to avoid
Cookies have a control surface: you can see them, clear them, block third-party ones, and browsers give you switches for all of it. A fingerprint has none of that. It is assembled from ordinary properties your browser has to expose to render pages — screen size, fonts, timezone, graphics behaviour — so there is nothing to delete afterwards and no setting that turns "being a browser" off.
That is why the practical defence is upstream: stop the scripts that collect the fingerprint from loading, rather than trying to undo the collection.
How to Reduce Fingerprinting
1. Use an features" class="doc-internal-link">Ad Blocker
Extensions like DNDShield block known fingerprinting scripts from loading in the first place. This is the most effective defense.
2. Use Firefox with Enhanced Tracking Protection
Firefox blocks known fingerprinting scripts in Strict mode: Settings → Privacy & Security → Enhanced Tracking Protection → Strict
3. Use Tor Browser
Tor makes all users look identical, defeating fingerprinting. However, it's slow for daily browsing.
4. Disable JavaScript (Extreme)
Most fingerprinting requires JavaScript. Disabling it breaks most websites but eliminates fingerprinting.
What DNDShield Does
DNDShield blocks known fingerprinting scripts before they execute:
- Canvas fingerprinting scripts
- WebGL fingerprinting
- AudioContext fingerprinting
- Font enumeration scripts
- Known fingerprinting domains (over 200 blocked)
FAQ
Can I be completely anonymous? No. Complete anonymity is nearly impossible. The goal is to make tracking significantly harder, not perfect.
Does incognito mode prevent fingerprinting? No. Incognito mode only prevents cookie storage. Your browser fingerprint is the same in incognito.