Pushing data in real time. (Long polling vs SSE vs Websocket vs QUIC with working example)

Long Polling, Server-Sent Events, WebSockets, and QUIC — four ways to keep your clients in sync. Here's exactly how they work, when to use them, and what you're giving up. Long Polling Long polling is HTTP pretending to be real-time. The client makes a normal HTTP request, but the server holds it open — sometimes for seconds or even minutes — until it has data to send. Once the response arrives, the client immediately fires off the next request. It's a clever trick, and it works everywhere HTTP works. That's its superpower. But every message costs a full request/response cycle, header overhead and all. How it works : Client polls -> Server waits -> Data arrives -> Server responds -> Connection closes -> Client immediately polls again. Best for Legacy system compatibility Low-frequency updates Strict corporate firewalls Simple fallback mechanism Pros Works everywhere, any proxy No special server setup Easy to understand Firewall friendly ### Cons HTTP overhead (new HTTP request each tim