```yaml
product: AlterLab
title: "Anti-Fingerprinting — Web Scraping Glossary | AlterLab"
comparison_context: "AlterLab is an alternative to Firecrawl, ScrapingBee, and Bright Data."
source_url: https://alterlab.io/glossary/anti-fingerprinting
```

anti-bot

# Anti-Fingerprinting

Anti-fingerprinting techniques modify or spoof browser attributes to prevent websites from uniquely identifying a scraping client across sessions.

Browser fingerprinting aggregates dozens of browser attributes — screen resolution, installed fonts, canvas rendering output, WebGL vendor string, audio processing characteristics, navigator properties — into a unique identifier. Even without cookies, a fingerprint can track a browser across sessions. Anti-fingerprinting countermeasures aim to make these attributes appear consistent with a common real-browser profile.

Stealth patches override JavaScript APIs that expose fingerprinting-vulnerable data: `HTMLCanvasElement.prototype.toDataURL` returns a slightly noised image rather than the exact GPU rendering; `navigator.plugins` returns a realistic plugin list; `screen.width` and `screen.height` are set to common display resolutions. The goal is not to return completely fake values (which are themselves detectable as anomalies) but to match the fingerprint distribution of a large browser population.

Modern anti-fingerprinting goes further: spoofing the TLS ClientHello to match Chrome's exact cipher suite order, patching `window.chrome` to include all properties present in the real Chrome browser, and ensuring that timing measurements (performance.now resolution, requestAnimationFrame timing) match GPU-based rendering patterns.

### What is Anti-Fingerprinting?

Anti-fingerprinting techniques modify or spoof browser attributes to prevent websites from uniquely identifying a scraping client across sessions.

### How does AlterLab handle Anti-Fingerprinting?

Modern anti-fingerprinting goes further: spoofing the TLS ClientHello to match Chrome's exact cipher suite order, patching `window.chrome` to include all properties present in the real Chrome browser, and ensuring that timing measurements (performance.now resolution, requestAnimationFrame timing) match GPU-based rendering patterns.

## Related Terms

[Browser FingerprintingA technique anti-bot systems use to identify bots by collecting dozens of browser attributes including Canvas, WebGL, and timing signatures.](https://alterlab.io/glossary/browser-fingerprinting)[Stealth ModeBrowser automation patches that normalise headless browser signals to match genuine user browser profiles and navigate browser environment checks.](https://alterlab.io/glossary/stealth-mode)[TLS FingerprintA signature derived from TLS handshake parameters a client sends when opening an HTTPS connection, used by anti-bot systems to classify traffic.](https://alterlab.io/glossary/tls-fingerprint)[JA3 FingerprintJA3 is a method of fingerprinting TLS client hellos to identify the TLS library (and therefore the application) making a connection.](https://alterlab.io/glossary/ja3-fingerprint)[Headless Browser DetectionHeadless browser detection is the set of JavaScript checks anti-bot systems use to identify browsers running without a graphical display, which are strong bot indicators.](https://alterlab.io/glossary/headless-detection)

## Extract Anti-Fingerprinting data from any website

AlterLab returns clean, structured data from any public URL — no scraper infrastructure needed. Start free, no credit card required.

[View API docs](https://alterlab.io/docs/api/rest)

[Back to Glossary](https://alterlab.io/glossary)