WebSocket

You might say

How does a chat room receive new messages in real time?

A connection that stays open, letting both sides send messages at any timeLive chat and collaborative editing may use WebSocket when both sides need frequent messages. An HTTP request and response form one message exchange, but the underlying HTTP connection can be reused and HTTP/2 can multiplex streams. After its handshake, WebSocket exchanges messages in both directions over one connection. Applications can add heartbeat checks and reconnection or state-recovery logic as needed; the connection can still drop.

Know first

HTTP

WebSocket

Ordinary requests versus WebSocket connections

Your page

AskAny new messages?ReplyNoAskAny new messages?Reply1 new messageAsk again each time; messages arriving within the interval wait for the next round

Server

Messages arriving within the polling interval are delayed; shorter intervals cost more requests.

Where message delay comes from in each

Polling waits for the next check: A new message may wait for the next check; shorter intervals mean more requests.

WebSocket can send proactively: An open connection lets the server send proactively, but actual delay also depends on server work, queues, network, and client rendering.

Both sides can send: It is not just server push: the client can send anytime over the same connection.

Quick checkChoose the best answer

A chat room is implemented by asking the server every second whether there are new messages. What problem does this cause?

Checking every second is real-time enough, no problemMake the page bigger so more messages show at onceMost per-second requests are empty polls, wasting requests and adding delay; real-time should use a persistent connection

You can say this to an AI Agent

The chat room currently polls for new messages every second. Switch to WebSocket: keep the connection open after it is established and push messages as they arrive. Auto-reconnect on disconnection; afterward confirm it is a persistent connection in the Network panel and test that messages resume after a network recovery.

Learn next

1Streaming Response→2HTTP→3Timeout→

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