Detecting Presence & Online Status
Build live online/offline indicators using Realtime Database presence, onDisconnect handlers, and the special .info/connected node to reflect connection state reliably.
What Is Presence
Presence means knowing which users are currently online. Chat apps, collaborative tools, and games all rely on it to show 'active now' indicators.
Realtime Database has special features that make presence robust even when a client disconnects unexpectedly.
The Connection Challenge
The hard part is the ungraceful disconnect: a user closes their laptop or loses signal. The app never gets to set status to 'offline'. We need the server to do it for us.
All lessons in this course
- Enabling Offline Persistence
- Handling Network Disconnections
- Data Synchronization Strategies
- Detecting Presence & Online Status