TanStack Query and live metrics

Dashboard uses two channels for “live” data:

Channel	API	Updates
TanStack Query	GET /api/metrics/summary	Stat cards every 5s
EventSource SSE	/api/events/stream	Activity table rows

playstepchallengeinstructor

TanStack Query

GET /api/metrics/summary · 5s poll

total_events: 42

Simulate poll tickPolls: 0

SSE live feed

EventSource team_event · Redis pub/sub

Simulate SSE eventLive rows: 0

createQuery(() => ({
  queryKey: ["metrics-summary"],
  queryFn: fetchMetricsSummary,
  refetchInterval: 5000,
}));

See apps/radar/src/api/client.ts.

Teach-back prompt

Why not poll SSE every 5 seconds instead?