LocalStorage Manager Free Online Tool 2026

Last updated March 22, 2026

Viewing All localStorage Entries

Open the LocalStorage Manager to see all data your browser has stored for the current origin. Example view for a web application:

LocalStorage Contents for: https://app.example.com
─────────────────────────────────────────────────────────────────────
Key                      Value (preview)              Size
─────────────────────────────────────────────────────────────────────
user_preferences         {"theme":"dark","lang":"en"} 42 bytes
auth_token               eyJhbGciOiJIUzI1NiJ9...      312 bytes
cart_items               [{"id":1,"qty":2},...]        156 bytes
last_visited_page        /dashboard/analytics          28 bytes
feature_flags            {"beta":true,"v2":false}      38 bytes
onboarding_completed     true                          4 bytes
─────────────────────────────────────────────────────────────────────
Total: 6 entries | 580 bytes used | ~5 MB available

Editing a User Preference

Click the user_preferences entry to edit it. The JSON value is displayed in formatted form:

Key: user_preferences

Current value (formatted):
{
  "theme": "dark",
  "language": "en",
  "fontSize": "medium",
  "notifications": true,
  "sidebarCollapsed": false
}

Edit: Change theme to "light" and fontSize to "large"

Updated value:
{
  "theme": "light",
  "language": "en",
  "fontSize": "large",
  "notifications": true,
  "sidebarCollapsed": false
}

✓ Saved — changes take effect immediately

The application will now render with the light theme and large font size on the next page load or state refresh.

Testing Feature Flags

Modify feature flags to test different application states without code changes:

Key: feature_flags

Current value:
{
  "betaFeatures": false,
  "newDashboard": false,
  "experimentalSearch": false
}

Edit: Enable beta features for testing

Updated value:
{
  "betaFeatures": true,
  "newDashboard": true,
  "experimentalSearch": false
}

✓ Saved — reload the page to see beta features

This lets you test feature-flagged code paths without needing a special test account or backend configuration change.

Adding a New Entry

Add a new localStorage entry to simulate a specific application state:

Add New Entry:
─────────────────────────────────────────────────────────────────────
Key:   onboarding_step
Value: 3

✓ Entry created

Now the application will think the user is on step 3 of onboarding,
allowing you to test the onboarding flow from that specific step
without completing steps 1 and 2.

Simulating a Returning User

Set up localStorage to simulate a user who has previously used the app:

Add entries to simulate returning user:

1. Key: first_visit_date
   Value: 2024-01-15T10:30:00Z

2. Key: visit_count
   Value: 47

3. Key: last_seen_announcement
   Value: announcement_v2_3

4. Key: dismissed_banners
   Value: ["welcome_banner","upgrade_prompt","survey_2024"]

These entries tell the application this is a returning user
who has visited 47 times and dismissed several banners.
Test that returning-user UI elements display correctly.

Inspecting a JSON Value

Expand a complex JSON value to inspect its full structure:

Key: cart_items

Full value (formatted):
[
  {
    "id": 1,
    "name": "Wireless Headphones",
    "price": 79.99,
    "quantity": 2,
    "variant": "black",
    "addedAt": "2024-01-20T14:22:00Z"
  },
  {
    "id": 5,
    "name": "USB-C Cable",
    "price": 12.99,
    "quantity": 1,
    "variant": "2m",
    "addedAt": "2024-01-20T14:25:00Z"
  }
]

Size: 312 bytes
Type: JSON Array (2 items)

Deleting Specific Entries

Remove individual entries to test how the application handles missing data:

Delete entry: auth_token

⚠ Warning: Deleting auth_token will log you out of the application
on the next request that requires authentication.

Confirm delete? [Yes] [Cancel]

✓ Entry deleted

Test: Reload the page — the application should redirect to the
login page because the auth token is no longer present.

Storage Quota Monitoring

The manager shows storage usage to help identify applications storing excessive data:

Storage Usage:
─────────────────────────────────────────────────────────────────────
Used:      2.3 MB  (46% of quota)
Available: 2.7 MB
Total:     5.0 MB

Largest entries:
  cached_api_response    1.8 MB  (78% of used storage)
  user_preferences       42 bytes
  auth_token             312 bytes

Warning: cached_api_response is using 1.8 MB.
Consider using IndexedDB for large data caching,
or implement cache expiration to prevent quota issues.

Exporting and Importing localStorage

Export the current localStorage state to share with a teammate for debugging:

Export localStorage as JSON:
{
  "user_preferences": "{\"theme\":\"dark\",\"language\":\"en\"}",
  "auth_token": "eyJhbGciOiJIUzI1NiJ9...",
  "cart_items": "[{\"id\":1,\"qty\":2}]",
  "feature_flags": "{\"beta\":true}",
  "last_visited_page": "/dashboard"
}

Share this JSON with your teammate. They can import it to
reproduce the exact localStorage state that caused the bug.

Import on another machine:

Import JSON → Paste the exported JSON → Click Import

✓ 5 entries imported
The localStorage state now matches the original environment.