What I Learnt Building a Real-Time Web App

The awkward part of a real-time interface is what happens after the connection drops. The screen may still look current while the data behind it has stopped changing.

I want the interface to say when it's reconnecting, and I want a plan for refreshing its state once the connection returns. Duplicate or late events need thought too. Sending an update is only part of the feature; helping the user know what they can trust takes more work.