GoKawiilMozilla study of 25 million Firefox users cuts fingerprint uniqueness from 75% to 46%
Mozilla, working with researchers from the University of Toronto and UC San Diego, measured browser fingerprinting uniqueness across nearly 25 million Firefox release users using privacy-preserving collection methods including OHTTP. The findings informed new anti-fingerprinting protections shipped in Firefox 143, which the study says reduced the share of users identifiable as unique by commercial fingerprinting tools from 75% to 46%. Mozilla has published the paper, an appendix, aggregate data, analysis code, and an interactive tool letting users compare their own browser against the measured population.
GoKawiil's interpretation of the reporting above, not reported fact.
The scale of the dataset, nearly 25 million users, gives researchers a rare unbiased view of how identifiable real browsers are, which could make future anti-tracking defenses more evidence-based rather than theoretical. Publishing the raw data, code, and methodology may let outside researchers verify Mozilla's results or propose further mitigations, strengthening industry-wide efforts against fingerprinting. The remaining 46% uniqueness figure suggests fingerprinting remains a substantial tracking risk even after these protections, indicating more work may be needed.
- Mozilla measured fingerprinting uniqueness across almost 25 million Firefox users using privacy-preserving techniques like OHTTP.
- New protections in Firefox 143 reduced unique-user identifiability from 75% to 46% against commercial fingerprinters.
- Mozilla released the full paper, aggregate data, code, and an interactive comparison tool for public scrutiny and follow-up research.
Privacy Screen Protector / VPN Router (browser privacy bundle) — If browser fingerprinting concerns you, pairing a hardware-level privacy tool like a dedicated VPN router with privacy-hardened browsing habits adds another layer of defense beyond browser settings alone. It's a practical complement to the fingerprinting protections discussed in this research, giving you network-level anonymity alongside browser-level mitigations.
See Privacy Screen Protector / VPN Router (browser privacy bundle) on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.Source: fingerprinting.study — Tom Ritter, 2026-11-10
Published there as: “A comprehensive study of how fingerprintable users are”
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