ClientSideTools Privacy-First Browser Tools

Cache Storage Inspector & Eviction Simulator

The Cache API is invisible outside DevTools. This tool lists every cache, enumerates entries with content types and sizes, and simulates how the browser's eviction would trim your cache under quota pressure — read-only, nothing is deleted.

PWA & Browser Storage Local processing Reads only data in the current origin. Nothing is uploaded or deleted.

Tool interface

Inspecting origin:

Storage estimate: loading…

Introduction

Service workers fill the Cache API with responses, but you can't easily see what's stored, how big it is, or what would be evicted when the browser runs low on space. This inspector surfaces all of it in one place.

How it works

  • Lists caches via caches.keys().
  • Opens each cache and enumerates requests with cache.keys().
  • Estimates entry size via response.clone().blob() and reads content type.
  • Simulates eviction by trimming entries until the total fits a target quota.

Privacy

All reads are local via the Cache API and Storage API. The tool never deletes data and never sends anything off-device. No account, no API key.

Limitations

  • Opaque (no-cors) responses report size 0 and empty headers.
  • Eviction simulation is heuristic; real eviction is browser-defined.
  • Very large caches cap the number of entries scanned for performance.

FAQ

Why do some entries show 0 bytes?

Opaque responses from no-cors fetches hide their body and headers, so the size can't be measured.

Does this delete my cache?

No. The tool is read-only. The eviction view is a simulation only.

Related tools

Version and changelog

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