Persistent Storage

Persistent Storage — navigator.storage.persist() asks the browser to protect stored data (IndexedDB, Cache API, service worker caches) from automatic eviction. Without persistence, the browser may clear site data under storage pressure.

How it works

if (navigator.storage && navigator.storage.persist) {
  const isPersisted = await navigator.storage.persist();
  console.log(isPersisted ? 'Storage is persistent' : 'Storage may be evicted');
}

• Returns a Promise<boolean> — true if the browser granted persistent storage.
• The browser may reject the request based on its own heuristics (e.g., user engagement). There is no guaranteed way to force persistence.
• navigator.storage.persisted() checks whether storage is already persistent without requesting it.

Browser & ecosystem support

Browser / Platform	Support	Since	Confidence	Source	Notes
Chrome (Desktop)	✅ yes	55	high	ref	—
Chrome (Android)	✅ yes	55	high	ref	—
Edge (Desktop)	✅ yes	79	high	ref	—
Firefox (Desktop)	✅ yes	57	high	ref	—
Firefox (Android)	✅ yes	57	high	ref	—
Safari (macOS)	✅ yes	15.2	high	ref	—
Safari (iOS)	✅ yes	15.2	high	ref	—
Samsung Internet	✅ yes	6.0	medium	ref	—

Source: spec · MDN · Last verified 2026-07-12 · Confidence: high

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