OpenParty is an open source project created and maintained by Nikolas de Hor, a developer based in Goiânia, GO, Brazil. The idea is simple: let two or more people watch a YouTube video or an MP4 file together, with play, pause and seek kept in sync across everyone in the room, no browser plugin and no account required.
One person pastes a video URL on the home page and creates a room. The server keeps the playback state in memory and broadcasts play, pause, seek, chat and reaction events over WebSocket to every connected participant. An NTP-style clock calibrates each participant's network delay to keep sync accurate even on different connections. When the person currently in control leaves the room, the server automatically hands control to whoever has been connected the longest.
The frontend is built with React and TypeScript using Vite. The server runs on Bun with the Hono framework, exposing REST and WebSocket on the same port. The event protocol shared between client and server lives in its own package inside the monorepo (pnpm plus Turborepo). The code is public on GitHub under the MIT license.
OpenParty is not a streaming service, does not host videos, and does not bypass content protection: it only synchronizes playback of a URL that the user themselves provides. DRM-protected services depend on a browser extension and a matching adapter, which is still under development.
To report an issue or suggest an improvement, see the contact page or open an issue on the GitHub repository.