How to Test Real-Time Features in Vibecoded Apps

Test the WebSocket or SSE connection lifecycle from start to finish. Verify that the connection establishes on page load, stays alive during normal use, and reconnects automatically after disruption. Use Chrome DevTools Network tab (filter by WS) to inspect WebSocket frames and connection status.

Simulate connection drops by toggling airplane mode or using DevTools to go offline. The app should detect the disconnection, show a clear indicator to the user, and attempt reconnection with exponential backoff. AI-generated real-time code often does not implement reconnection at all, or tries to reconnect too aggressively, flooding the server with requests.

Open your app in two browser windows side by side and perform actions in one that should appear in the other. Verify that changes propagate within a reasonable time (under 1 second for most use cases). Test what happens when both clients make conflicting changes simultaneously — the app should have a strategy for conflict resolution, whether it is last-write-wins, operational transforms, or CRDTs.

Test with more than two clients to check for scaling issues. AI-generated real-time code sometimes broadcasts messages to all clients including the sender, causing duplicate updates or infinite loops. Verify that each client sees a consistent state and that the server remains the source of truth.

Send multiple messages rapidly and verify they arrive in the correct order. Network conditions can cause messages to arrive out of sequence, and your app needs to handle this. In a chat application, messages should always display in chronological order regardless of delivery timing.

Test message delivery guarantees: if a message is sent while the connection is temporarily down, it should be queued and delivered when the connection is restored. Verify that no messages are silently lost. Also test with large messages or high-frequency updates to check that the app remains stable under load.