How do you implement real-time features in SvelteKit?

Real-time features in SvelteKit via multiple approaches: Server-Sent Events (SSE): server pushes events to clients over a persistent HTTP connection. Create a +server.js endpoint that returns a ReadableStream: return new Response(new ReadableStream({ start(controller) { const send = (data) => controller.enqueue(\`data: \${JSON.stringify(data)}\n\n\`); const interval = setInterval(() => send(getUpdate()), 1000); request.signal.addEventListener('abort', () => clearInterval(interval)); } }), { headers: { 'Content-Type': 'text/event-stream' } }). Client subscribes with new EventSource('/events'). WebSockets: SvelteKit doesn't have built-in WS support, but add them in the Vite plugin or via the adapter's hooks (e.g., adapter-node exposes the HTTP server). PartyKit: a platform purpose-built for SvelteKit real-time — add WebSocket rooms with a single import. Polling: simplest — use invalidate() to refresh load function data periodically.