WatchTogether is a Chrome extension developed by linsen that allows multiple PC devices to synchronize video playback progress. With this extension, users can create a room and invite others to join, ensuring that everyone is watching the same video at the same point in time.

Currently, WatchTogether supports popular video streaming websites such as Bilibili, Youtube, Lqiyi, AcFun, and YouKU. This makes it convenient for users to enjoy their favorite videos together, regardless of the platform they are using.

The implementation of WatchTogether is straightforward, with a codebase of less than 1000 lines. This simplicity allows for easy expansion and modification in the future. The technology stack used includes Python, Flask, React, Webpack, and Websocket.

For those interested in exploring the code, the frontend code for WatchTogether is available on GitHub at [link to frontend repository], while the backend code can be found at [link to backend repository].