ClientSideTools Privacy-First Browser Tools

Storage Persistence Auditor

Is your app's data safe from the browser's eviction? This tool reports whether your origin's storage is best-effort (can be cleared under storage pressure) or persistent, shows your quota usage, and helps you request persistence.

PWA & Browser Storage Local processing Reads only your origin's storage state. Nothing is uploaded.

Tool interface

Auditing origin:

Introduction

Offline-first PWAs rely on IndexedDB, Cache Storage, and LocalStorage surviving between visits. But by default, browsers treat storage as "best-effort" and can evict it when space is low. Knowing your persistence mode is essential to avoid surprise data loss.

How it works

  • Reads navigator.storage.persisted() for the current mode.
  • Reads navigator.storage.estimate() for usage and quota.
  • Computes eviction risk from the usage/quota ratio and the mode.
  • Offers a live navigator.storage.persist() request and a code snippet.

Privacy

All reads are local via the Storage API. No data leaves the origin. No account, no API key.

Limitations

  • Browsers may refuse persistence requests silently (policy-dependent).
  • The Storage API is unavailable in some contexts (e.g., certain private modes).
  • Per-API storage breakdown (IndexedDB vs Cache) is not exposed by the standard API.

FAQ

What is the difference between best-effort and persistent?

Best-effort storage can be cleared automatically when the device runs low on space. Persistent storage is protected from that automatic eviction.

Is my data uploaded?

No. Everything is read locally in your browser.

Related tools

Version and changelog

  • Version: 1.0.0
  • Last updated: August 12, 2026
  • Changelog: Initial production release.