Local Storage Sync

A Chrome Extension (Manifest V3) for syncing selected localStorage values from source domains to target domains.

Features

• Sync one or more localStorage keys across domains
• Configure source domains from the extension settings page
• Configure target domains from the extension settings page
• Choose which keys should trigger a reload confirmation on target pages
• Keep public repository defaults clean while allowing private local defaults for internal sharing

Public-safe defaults

This repository ships with safe public defaults in defaults.public.json.

• sourceDomains is empty
• targetDomains is empty
• storageKeys is empty
• confirmReloadForKeys is empty

The extension loads defaults directly from JSON files at runtime.

Internal local defaults

If you want private default domains for internal teammates without publishing them to GitHub:

1. Copy defaults.local.example.json to defaults.local.json
2. Put your private domains and storage keys in defaults.local.json
3. Load or reload the unpacked extension

defaults.local.json is ignored by git, so it stays local to each machine.

Installation

1. Open chrome://extensions
2. Enable Developer mode
3. Click Load unpacked
4. Select this folder

Configuration

1. Open the extension details page in Chrome
2. Click Extension options
3. Update source domains, target domains, and synced localStorage keys
4. Save settings
5. Refresh the tabs you want the new settings to affect

Files related to defaults

• defaults.public.json: public fallback defaults used automatically
• defaults.local.example.json: sample private defaults file
• defaults.local.json: local override defaults used automatically when present
• build-defaults.mjs: optional helper if you still want to generate defaults.js

Notes

• The extension syncs values only for origins listed in settings
• Reload confirmation is shown only for keys listed in Prompt page reload for these keys
• Latest values are kept in extension memory while the service worker stays alive
• Saved settings in extension storage can still override defaults after first use