LocalSync Extension

This extension copies localStorage data from a source environment and writes it to a target environment under the same key, then reloads the target page.

Browser Support

This extension is available for both Chrome/Edge and Firefox browsers.

Configure

Click the settings (⚙️) button in the popup:

• Source Environment URL: The URL where you want to read localStorage from (e.g., https://dev.example.com)
• Target Environment URL: The URL where you want to write localStorage to (e.g., http://localhost:3000) - optional, defaults to http://localhost:3000
• localStorage Key: The key to sync (e.g., access_token)

Installation

Chrome/Edge

1. Go to chrome://extensions (or edge://extensions)
2. Enable "Developer mode"
3. Click "Load unpacked" and select the chrome/ folder
4. Pin the extension

Firefox

Temporary Installation (for testing)

1. Open Firefox and navigate to about:debugging
2. Click "This Firefox" in the left sidebar
3. Click "Load Temporary Add-on..."
4. Navigate to the firefox/ folder and select manifest.json
5. The extension will load temporarily until you restart Firefox

Permanent Installation (for development)

Package the extension as an .xpi file or sign it with Mozilla and submit to Mozilla Add-ons for review and distribution.

Usage

1. Open your source environment and ensure the data is in localStorage
2. Open or ensure target environment is running
3. Click the extension icon:
   • It reads the data from source tab
   • Writes it into target's localStorage with the same key
   • Reloads target automatically

Notes

• Works with any localStorage key-value pair
• Supports any source and target URLs
• All settings are saved and persist across browser sessions

Browser-Specific Differences

Chrome/Edge (chrome/ folder)

• Uses chrome API
• Manifest V3 with service worker

Firefox (firefox/ folder)

• Uses browser API
• Manifest includes browser_specific_settings section
• Uses background scripts instead of service worker
• Requires Firefox 109 or later

Troubleshooting

General

• "No source tab open": Open your source environment URL in a browser tab
• "Data not found": Confirm the key exists in localStorage; verify in DevTools > Application > Local Storage
• Update source/target URLs in settings if needed

Firefox-Specific

• "about:debugging" shows error: Ensure Firefox is version 109+
• Extension not loading: Check browser console (Ctrl+Shift+K) for errors
• Sync fails: Ensure both source and target tabs are open and URLs are correct