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Developer ToolsUpdated 2025-04-11

Browser Storage Viewer: Explore localStorage and sessionStorage Visually

See everything stored in your browser localStorage and sessionStorage in a clean table. Search, inspect values, and understand what web apps are saving on your device.

Introduction

Modern web apps store a surprising amount of data in your browser. Theme preferences, authentication tokens, shopping cart contents, form drafts, analytics identifiers. Our Storage Viewer gives you a visual dashboard for both localStorage (persistent) and sessionStorage (cleared when you close the tab), presented as a searchable table with key names, values, sizes, and data types. Developers use it for debugging state issues, and curious users use it to see exactly what sites are storing on their machine.

Step-by-Step Guide

1

Switch between storage types

Use the tabs at the top to toggle between localStorage and sessionStorage. localStorage persists until manually cleared, while sessionStorage disappears when you close the browser tab.

2

Browse or search entries

Scroll through the table to see all stored key-value pairs. Use the search bar to filter by key name or value content. The size column shows how much space each entry uses.

3

Inspect JSON values

Many apps store complex data as JSON strings. Click a row to expand the value, and the tool will attempt to parse and pretty-print JSON values so they are actually readable instead of a wall of text.

Pro Tips & Best Practices

Pro Tip

Web apps have a storage quota of about 5 to 10 MB per origin. If a site feels slow, check if it is storing excessive data. The storage usage bar at the top shows your current utilization.

Pro Tip

When debugging a React or Vue app that uses localStorage for state persistence, this tool lets you see the stored state without adding console.log statements everywhere.

Pro Tip

Before clearing storage, note which keys look important. Clearing a site "auth_token" will definitely log you out, and clearing "cart" will empty your shopping cart.

Common Mistakes to Avoid

Common Mistake to AvoidTreating localStorage as a secure storage mechanism. Any JavaScript on the page can read all localStorage values, including malicious scripts from XSS attacks. Never store sensitive tokens in localStorage.
Common Mistake to AvoidThinking sessionStorage is shared between tabs. Each browser tab has its own independent sessionStorage. Opening a second tab to the same site gives it a fresh, empty sessionStorage.
Common Mistake to AvoidClearing all storage to "fix" a broken website without checking what you are deleting. You might lose saved preferences, draft content, or important application state.

Frequently Asked Questions

What is the difference between localStorage and sessionStorage?

localStorage persists indefinitely until you or the site explicitly clears it. sessionStorage is automatically wiped when you close the browser tab. Both are limited to the same origin (domain + protocol + port).

Can websites access each other storage?

No. Browser storage is sandboxed per origin. A script on example.com cannot read the localStorage of another-site.com. This is enforced by the browser same-origin policy.

How much data can a site store?

The typical limit is 5 MB for localStorage and 5 MB for sessionStorage per origin, though some browsers allow more. IndexedDB provides much larger limits for apps that need significant client-side storage.

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