---
title: "Browser fingerprinting"
url: https://proxy.wiki/glossary/browser-fingerprinting/
type: Glossary Term
author: "proxy.wiki editorial"
published: 2026-08-19
updated: 2026-08-19
site: proxy.wiki
topics: ["Proxy fundamentals"]
license: CC BY 4.0 — quote freely with attribution to https://proxy.wiki/
---

# Browser fingerprinting

> Building an identifier from browser and device characteristics exposed to JavaScript.

**Browser fingerprinting assembles a large number of small, individually unremarkable properties into an identifier that is often unique.** It runs in JavaScript once the page loads.

## Properties commonly collected

- Screen dimensions, colour depth, device pixel ratio.

- Installed fonts, detected by measuring rendered text.

- Canvas and WebGL output, which vary with GPU and driver.

- Audio stack behaviour.

- Timezone, language, platform, hardware concurrency.

- Available plugins and supported media types.

## Why automation is easy to spot

Headless browsers historically exposed direct tells such as `navigator.webdriver`. Those are patchable, but internal consistency is much harder to fake: a fingerprint claiming macOS with Linux font metrics, or a GPU renderer string that no consumer machine reports, stands out precisely because real devices are consistent.

## The practical implication

Changing your address does nothing here. A pristine [residential](/glossary/residential-proxy/) exit combined with an implausible fingerprint is still identifiable — and the combination can look worse than either problem alone.