WebSockets와 HTTP 폴링 비교

In modern apps, waiting is not an option — we expect instant chat, prices, and scores. It all comes down to how the client and server communicate.

HTTP polling is the oldest trick: the client asks the server for new data at fixed intervals, getting a response even when nothing has changed.

Here is the basic idea of polling in JavaScript — the client fetches data on a fixed timer, say every five seconds.

Polling is simple but wasteful: high latency since updates wait for the next poll, plus empty responses and constant connection churn burn resources.

Long polling improves things: the server holds the request open until new data is ready or it times out, making HTTP feel more real-time.

The long polling flow: client requests, server waits and responds only when data arrives (or times out), then the client immediately reopens the request.

Long polling still has costs: each update is a fresh request cycle, it stays one-directional, and many held-open requests strain the server.

WebSockets were built to fix polling: a true persistent, bidirectional channel over one TCP connection. Think a phone call, not letters back and forth.

WebSockets win on every axis: full-duplex messaging, a persistent connection after one handshake, low overhead, and instant server-to-client pushes.

Quick recap: polling is high-latency, long polling improves it but keeps HTTP overhead, and WebSockets give a persistent, low-latency full-duplex link.

Which of the following is a primary advantage of WebSockets over HTTP polling and long polling for real-time applications?

You compared the techniques: HTTP polling is simple but inefficient, long polling improves latency, and WebSockets enable instant two-way communication. Next: the protocol itself.