Suggest an editImprove this articleRefine the answer for “What is WebSocket?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**WebSocket** is an application-layer protocol that provides a persistent, two-way connection between a client and a server. It lets a client and a server "talk" in real time. **Key point:** the connection is established once and stays open, so the server can send data to the client on its own without waiting for a new request.Shown above the full answer for quick recall.Answer (EN)Image**WebSocket** is an **application-layer protocol** that provides a **persistent, two-way connection between a client and a server**. In short: **WebSocket lets a client and a server "talk" in real time**. --- ## Why WebSocket is needed Plain HTTP works like this: - the client sends a request - the server responds - the connection ends This is inconvenient when you need to: - get updates instantly - exchange messages continuously - avoid waiting for a new request from the client **WebSocket solves this problem**. --- ## The core idea of WebSocket **The connection is established once and stays open**. After that: - the client can send data to the server **at any moment** - the server can send data to the client **without being asked** This is called a **two-way (full-duplex) connection**. --- ## How WebSocket works (simplified) 1. The client connects to the server over HTTP 2. An "upgrade" happens - a switch from HTTP to WebSocket 3. A persistent connection is established 4. The client and server freely exchange messages No repeated requests or waiting. --- ## Where WebSocket is used Typical examples: - online chats - messengers - stock quotes - online games - real-time notifications - collaborative editors (Google Docs and similar tools) Anywhere **minimal latency** matters. --- ## WebSocket vs HTTP (in short) - **HTTP** - request → response - no persistent connection - the server cannot initiate sending data on its own - **WebSocket** - persistent connection - the server can send data on its own - suits real-time use cases --- ## A real-life example HTTP is like corresponding by email: you write → you wait → you get a reply. WebSocket is like a phone call or a chat: you can talk at any moment and get a reply right away. --- ## Short answer for the interview Remember this phrasing: > **WebSocket is an application-layer protocol that establishes a persistent, two-way connection between a client and a server and is used to exchange data in real time.**For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.