LiveBeats: Building a social music app with Phoenix LiveView

Summary

LiveBeats is an open-source social music application built as a full-stack Phoenix reference app and learning test bed for LiveView features. It demonstrates a shared real-time UI for playlist playback, presence, GitHub OAuth, and concurrent MP3 uploads, using Phoenix PubSub and the existing LiveView WebSocket connection rather than separate REST, JSON, or polling layers. Uploads are processed concurrently in temporary files to verify MP3 validity and enforce a duration below 20 minutes, while HEEx function components and slots provide reusable UI and JS commands keep immediate interactions such as modal hiding on the client. The application runs across five continents with automatic clustering, file proxying, and regional Postgres read replicas; the post presents this as a way to deliver responsive global behavior with relatively minor changes.

Takeaways

1. 1

   Phoenix PubSub lets LiveBeats broadcast business events and have connected LiveViews update their interfaces, including across horizontally scaled servers.

2. 2

   LiveView uploads use the existing WebSocket connection; temporary files stay on the LiveView's load-balanced instance while MP3s are concurrently parsed, verified, and checked for a duration under 20 minutes.

3. 3

   LiveBeats was deployed across five continents with automatic clustering, file proxying between regions, and Postgres read replicas for mostly static data, requiring only minor changes.