In 2018, I worked on a project called Dancing Together to enable my girlfriend and I to listen to music together while we were long distance.
The README summarizes it well:
Dancing Together is a website for friends, family, couples, coworkers, and even Internet strangers to listen to Spotify together. Simply sign up for an account, create or join a room with friends, select some killer tunes, and hit play. Each person listens to music using their own Spotify account and Dancing Together keeps the jammin’ in sync. Pause it, skip it, rewind it, enjoy it!
Why I started this project
Before creating this website, we tried listening to music over Skype, FaceTime, and Google Hangouts, but the latency always made the experience less enjoyable for the person not playing the music locally. It would sound metallic, would be too metallic, or would be too quiet/loud compared to our voices.