Files
KoalaSync/extension
2026-06-19 14:39:06 +00:00
..
2026-06-04 15:33:06 +02:00

KoalaSync Browser Extension

A Manifest V3 Browser Extension (Chrome & Firefox) for synchronized video playback across any website.

Key Features

  • Manifest V3: Optimized Service Worker architecture with session persistence.
  • Pure Vanilla JS: No external dependencies or heavy libraries.
  • Smart Peer IDs: Hexadecimal IDs combined with customizable Usernames for easy identification.
  • On-Demand Connection: The service worker only maintains a WebSocket connection while you're in a room. No persistent background connections — privacy-first architecture. Based on connectIntent flag that gates all reconnect attempts.
  • Live Diagnostics: Built-in "Dev" tab for real-time video state debugging (ReadyState, CurrentTime, etc.).
  • Dynamic i18n (Multi-Language): Fully localized in 13 languages (en, de, fr, es, it, pl, tr, nl, ja, ko, pt-BR, pt, ru) with auto-detected fallback and dynamic on-the-fly language selectors.

Tab Overview

  1. Room: Manage connections, view active peers, and share invitation links.
  2. Sync: Control video playback (Play/Pause/Force Sync) and view recent activity.
  3. Settings: Customize your Username, toggle domain-based Noise Filtering, and switch the App Language.
  4. Dev: Monitor connection status and view real-time video element metadata for debugging.

Privacy & Permissions

KoalaSync requires <all_urls> permission to detect and interact with video elements (<video>) on websites.

  • No Browsing History: We do not track or store your browsing history.
  • State Management: Sensitive data (Room Passwords) is stored locally using chrome.storage.
  • Zero Telemetry: No analytics or external tracking scripts.
  • Zero Runtime Dependencies: The extension is built with pure Vanilla JS and contains no external libraries or tracking scripts, ensuring performance and privacy.

Installation

  1. Prepare Extension: From the repository root, run:
    npm run build:extension
    
  2. Open Chrome and go to chrome://extensions/.
  3. Enable Developer mode (top right).
  4. Click Load unpacked and select the dist/chrome folder.

Development

If you modify shared/constants.js, you must synchronize the changes by running the build script from the root:

npm run build:extension

This ensures that the extension/shared folder is updated with the latest protocol constants.

Module Structure

File Purpose
background.js Service worker: message routing, tab listeners, startup
content.js Video detection, audio processing, episode transition (IIFE)
popup.js Popup UI: join/create, tabs, status, settings
bridge.js Landing page bridge (injected into sync.koalastuff.net)
episode-utils.js Shared extractEpisodeId() / sameEpisode() — used by background.js, injected into content.js at build time
i18n.js Translation loader
shared/ Constants, blacklist, name generator