Lukas Mateffy _


Peer-to-peer group video calls
and Spotify playback sync


  • Peer-to-peer group video chat using PeerJS
  • Listen to your favourite music together by synchronizing your Spotify playback
  • Room based authentication: You only need a link to join!


  • Mini games to play together

How it works

Video chat

The server has a list of all connected peers, that every peer has access to. When this list changes, the newly added peer will try to call all peers on the list using PeerJS.

However, since this approach does not support things like end-to-end encryption, I’m thinking about switching the call architecture to one based on JitsiMeet

Spotify Playback Sync

The server has a queue of songs created and edited by the users in the current room, that every client has access to. A user can also authenticate Spotify in the page, which gives the SPA API access to Spotify.

Once the list changes by adding, removing or moving a song, every client will then create or update a playlist called SAUF.CHAT - Queue in the user’s Spotify account and add / remove the respective songs.

The server then keeps track of when the playback was started and how long each song in the list is. That way, we don’t rely on play/pause events being passed to the respective clients for timing the playback correctly, but by having a deterministic playback structure.

By knowing the length of the songs and when the playlist was started, we can calculate where to skip to, should you join later. Actually playing the next song is done by Spotify tho, because we simply let it play the playlist.

The project displayed inside a device. The project displayed inside a device.


Beta v0.1.423 – Spotify release

  • Added Spotify sync

Beta v0.1.0 – First release

  • Working video chat


Year: 2020
Platform: macOS
Tech: JavaScript, Vue