Sweep — Browser Tab Garbage Collector

Focus on what matters. Sweep the rest.

Sweep is a browser extension for Firefox and Zen that intelligently manages open tabs by discarding inactive ones to reduce memory usage. Unlike simple time-based tab managers, Sweep uses a unified scoring algorithm that balances recency (how recently you accessed a tab) and frequency (how often you switch to it) to decide which tabs to keep active.

Features

• Unified scoring algorithm combining recency + frequency weights
• Automatic periodic sweeping via browser alarms
• Domain whitelist (tabs on whitelisted domains are never discarded)
• Protection rules: pinned tabs, audible tabs, and the active tab are always safe
• Manual sweep trigger via popup button
• Minimal, clean settings UI built with Svelte 5
• Dark mode support

Requirements

• Node.js ≥ 18 (or Bun ≥ 1.0)
• Firefox ≥ 109 or Zen Browser
• macOS (build tested on macOS; Linux should work similarly)

Setup

# Install dependencies
bun install

Build

# Build the extension
bun run build

# Create a clean zip for submission
bun run zip

The built extension will be at .output/firefox-mv3/.
The submission zip will be at .output/sweep.zip.

Development

# Start dev server with hot reload
bun run dev

This opens a new Firefox profile with the extension pre-installed and hot module replacement enabled.

Architecture

Sweep treats tabs like a memory management problem:

• Active tabs = "hot memory" (high score)
• Inactive tabs = "cold memory" (low score, candidates for discard)

The sweep algorithm:

1. Get all normal tabs
2. Filter out protected tabs (active, pinned, audible, whitelisted domain)
3. Filter out tabs younger than minInactivityMinutes
4. Score remaining tabs: score = recencyWeight × recencyNorm + frequencyWeight × frequencyNorm
5. Sort ascending by score (lowest = discard first)
6. Discard lowest-scoring tabs until tab count ≤ maxActiveTabs

Settings

Setting	Description	Default
enabled	Toggle Sweep on/off	true
maxActiveTabs	Hard cap on kept tabs	10
minInactivityMinutes	Minimum tab age before eligible	10
recencyWeight	How much recency matters (0–10)	6
frequencyWeight	How much frequency matters (0–10)	4
whitelistDomains	Domains that are never discarded	[]
sweepIntervalMinutes	Time between automatic sweeps	5