Automatically discards heavy tabs to free RAM while keeping them visible in your tab bar. Built for personal use to manage memory-hungry sites like SharePoint, Slack, and Asana.
Chrome's built-in memory saver is too generic. This extension targets specific sites that consistently consume excessive RAM, discarding them on a schedule while protecting tabs you're actively using.
- Targeted auto-discard: Configure which sites to discard (add your own via Dashboard)
- Reliable scheduling: Uses Chrome's Alarms API to survive service worker sleep
- Configurable intervals: Run every 5, 10, 15, or 30 minutes
- Idle tab detection: Automatically discard tabs not viewed for N hours
- Manual override: One-click to discard all tabs immediately
- Active tab protection: Never discards the tab you're currently viewing
- Behavior analytics: Track tab usage patterns to optimize discard rules
- Data retention: Automatic cleanup of old telemetry data (configurable)
- Type-safe: Written in strict TypeScript
# Install dependencies
npm install
# Build the extension
npm run build
# Run tests
npm test
# Type check
npm run typecheck
# Lint
npm run lint- Navigate to
chrome://extensions/ - Enable "Developer mode"
- Click "Load unpacked" and select the
dist/directory - Pin the extension to your toolbar
Click the extension icon → toggle "Auto-discard" on → select interval → choose target sites.
"Discard All Tabs Now" button discards everything except:
- Active tab (prevents disruption during screen sharing)
- Extension pages
- Chrome internal pages
"View Dashboard" opens a full-page analytics view showing:
- Top domains by tab count
- Most active tabs (by view count and time)
- Most discarded sites
- Recent discard events with timestamps
Export data as JSON for custom analysis.
In the Dashboard, you can:
- Add custom domains (e.g.,
jira.atlassian.comor partial matches likejira) - Remove built-in or custom sites
- Configure idle threshold (auto-discard tabs not viewed for X hours)
Uses Chrome's native tabs.discard() API to unload tabs from memory. Discarded tabs remain visible in the tab bar but show a blank page until clicked.
Key behaviors:
- Uses
chrome.alarmsAPI for reliable scheduling (survives service worker sleep) - Skips active tabs (prevents closing what you're viewing)
- Skips already-discarded tabs (no redundant work)
- Skips extension and chrome:// pages (prevents breaking Chrome)
- Logs all activity to IndexedDB for pattern analysis
- Automatically purges old telemetry data (30 days default)
Tracks tab behavior locally in IndexedDB:
- Tab creation, activation, updates, removal
- Active time per tab
- Discard events with timestamps and reasons
- Opener relationships (which tab spawned which)
Privacy: All data stays local. No network requests. No external transmission.
Data Retention: Old events are automatically purged after 180 days (configurable in Dashboard).
offloader/
├── manifest.json # Extension configuration
├── package.json # Dependencies and scripts
├── tsconfig.json # TypeScript configuration
├── vitest.config.ts # Test configuration
├── .eslintrc.json # ESLint rules
├── .prettierrc # Prettier configuration
├── icons/ # Extension icons (16, 48, 128px + SVG source)
├── scripts/ # Optional automation scripts
│ └── trigger-discard.sh # AppleScript for cron (macOS)
├── src/
│ ├── html/
│ │ ├── popup.html # Extension popup UI
│ │ └── dashboard.html # Analytics dashboard
│ ├── ts/
│ │ ├── types.ts # Type definitions and validation
│ │ ├── telemetry.ts # IndexedDB wrapper
│ │ ├── background.ts # Service worker (main logic)
│ │ ├── popup.ts # Popup controls
│ │ ├── dashboard.ts # Analytics visualization
│ │ └── *.test.ts # Unit tests
│ └── test/
│ └── setup.ts # Test setup and Chrome API mocks
└── dist/ # Build output (git-ignored)
- Language: TypeScript (strict mode)
- Manifest: v3 (latest Chrome extension standard)
- Permissions:
tabs,storage,alarms - Storage: IndexedDB for telemetry, chrome.storage.local for settings
- Architecture: Service worker with alarm-based scheduling
- Testing: Vitest with fake-indexeddb
- Security: DOM APIs only (no innerHTML), input validation
| Command | Description |
|---|---|
npm run build |
Compile TypeScript and copy assets to dist/ |
npm run build:watch |
Watch mode for development |
npm run lint |
Run ESLint |
npm run lint:fix |
Auto-fix ESLint issues |
npm run format |
Format with Prettier |
npm run typecheck |
Type check without emitting |
npm test |
Run tests |
npm run test:watch |
Watch mode for tests |
npm run test:coverage |
Run tests with coverage |
For scheduled execution independent of the extension timer:
# Add to crontab (macOS)
30 14 * * * /path/to/offloader/scripts/trigger-discard.shThe script uses AppleScript to simulate the keyboard shortcut. Requires Chrome to be running.
- Cannot access memory usage per tab (Chrome API doesn't expose this)
- Cannot track tabs opened before extension installation
- Telemetry only tracks tabs while extension is active
| Decision | Rationale |
|---|---|
| TypeScript | Type safety, better refactoring, catch bugs at compile time |
chrome.alarms |
Reliable scheduling that survives service worker sleep |
| IndexedDB | Unlimited storage for long-term telemetry |
| DOM APIs | XSS prevention (no innerHTML with user data) |
| Vitest + fake-indexeddb | Fast, modern testing with IndexedDB support |
| No build-time bundling | Simple Chrome extension loading, source maps for debugging |
- Breaking: Requires build step (
npm run build) - Added: TypeScript with strict mode
- Added: Chrome Alarms API for reliable scheduling
- Added: Data retention policy (auto-purge old events)
- Added: Input validation for all user inputs
- Added: Unit tests with Vitest
- Fixed: Service worker sleeping issue (using alarms instead of setInterval)
- Fixed: Potential XSS via innerHTML (now uses DOM APIs)
- Improved: Type-safe message passing between components
- Initial release
MIT License. Available on the Chrome Web Store.