KoalaSync

KoalaSync is a completely free, open-source browser extension that lets you synchronize video playback with friends across multiple devices. It was built as a privacy-first, lightweight alternative to commercial watch-party tools that force you to create accounts or track your viewing habits.

Whether you are watching Netflix, Prime Video, YouTube, or streaming from your own self-hosted media server like Emby, Jellyfin, or Plex, KoalaSync ensures everyone stays perfectly in sync.

Key Features: • Zero Tracking & No Accounts: No sign-ups required. Just create a room, share the link, and start watching. The server keeps no logs, has no database, and respects your privacy. • Universal Compatibility: Works on almost any website with a standard HTML5 <video> tag. • Self-Hostable: While a free public relay server is provided, you can easily spin up your own private server in seconds using the official Docker image. • Binge-Ready: Features Episode Auto-Sync. The room automatically waits until everyone has loaded the next episode before hitting play. • Extremely Lightweight: Built with pure Vanilla JS and zero library overhead for maximum performance in your browser. • Multi-Language Support: The extension is fully localized in 13 languages.