Font fingerprinting is an advanced browser-tracking technique that probes which system fonts are installed—and in what order—to build a unique identifier for each device. Because font libraries differ across operating systems, locales, and personal installs, the resulting "font map" becomes a powerful signal for user re-identification even when cookies are cleared.
How Font Fingerprinting Works
- JavaScript quietly renders text in a long list of test fonts.
- The script measures each rendering's width/height to detect whether that font exists.
- The final presence/absence pattern forms a near-unique fingerprint.
Risks for Scrapers & Automation
- Persistent tracking: Sites can recognise returning sessions despite IP changes.
- Account clustering: Multiple accounts run from one machine may be linked together.
- Higher ban rates: Anti-bot services flag mismatched or repeating fingerprints.
Defeating Font Fingerprinting with Proxied
- Use an antidetect browser to virtualise font lists or randomise them per profile.
- Rotate real mobile IPs through Proxied's 4G/5G proxy pool so each session not only shows a fresh fingerprint but also originates from a genuine carrier network.
- Adopt sticky sessions wisely: When you need continuity (e.g., logged-in posting), keep a sticky mobile IP yet still rotate the fingerprint via browser profile.