Realtime Integration Patterns

Polling Strategy

setInterval(async () => {
  const res = await fetch("/v1/cards/:id");
  const next = await res.json();
  updateIfPriceChanged(next);
}, 30_000);

Backoff + Stability Rules

• Use 15-30s refresh for active watchlists, 60-120s for background pages.
• Apply exponential backoff when HTTP `429` or `5xx` is returned.
• Only re-render rows/cards whose price fields changed.
• Debounce UI notifications so users are not spammed by micro-moves.

Preparing for Streams

Keep your client update pipeline transport-agnostic: one reducer for updates, multiple transport adapters (polling now, stream later).