v148 · Privacy · Storage

Storage Privacy Tester

Read your browser's reported storage quota live, then simulate the incognito fingerprinting attack this Chrome 148 change closes. Before Chrome 148, a dramatically lower quota reliably revealed incognito mode — Chrome 148 makes the reported value predictable enough to break this heuristic.

Live storage estimate

quota

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Click "Read quota"

usage

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bytes used

available

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quota − usage

used %

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of quota

the fingerprinting attack

// Pre-Chrome-148 incognito detection via storage quota
const { quota } = await navigator.storage.estimate();

// In regular Chrome: quota ≈ 60%+ of disk space (e.g. 50 GB)
// In incognito Chrome (pre-148): quota ≈ 120 MB (much smaller)

const INCOGNITO_THRESHOLD = 120 * 1024 * 1024; // 120 MB
const probablyIncognito = quota < INCOGNITO_THRESHOLD;

// Chrome 148 fix: report a consistent, predictable quota
// regardless of incognito status → heuristic becomes unreliable

implementation reference

Need the exact API surface, compatibility boundaries, errors, lifecycle, and source links? Read the matching gendn reference ↗