Metastream

Metastream is a web-based platform that enables real-time, synchronized playback of media for groups. Users can create or join rooms via a URL, invite others, and collectively watch videos and listen to audio from a variety of online sources. A shared media queue, chat, and room-wide controls help coordinate the viewing experience, while individual participants can adjust their own playback settings as allowed by room permissions.

Supported sources include players embedded in web pages, such as YouTube and Vimeo, among others. Because playback depends on the host page's browser, DRM-restricted content and some streaming services may be limited or blocked by policy or site. The platform focuses on browser-based playback and does not stream video data itself; it synchronizes control signals and timestamps across clients to keep everyone in sync.

Technically, Metastream follows a client-server model. A central server coordinates room state and shares it with connected clients through a real-time protocol, while the browser clients render the media and interface. The project is open-source, with client and server components that can be run locally or self-hosted, and it also offers hosted services for users who prefer not to deploy their own server.

Metastream emerged to facilitate remote or socially distant co-watching and has been adopted for casual gatherings, study groups, and online events. It is described as a general-purpose co-watching tool that operates independently of any single streaming service, serving as a shared control layer for synchronized media playback.