What is real-time communication?

Real-time communication refers to data exchange that occurs with minimal latency, enabling near-instantaneous delivery of information between sender and receiver. In web applications, it means the server can push updates to clients immediately when data changes, without requiring the client to poll repeatedly. Examples include: live chat messages appearing instantly, stock prices updating as trades happen, collaborative document editing showing other users' cursors and keystrokes in real time, and sports scores updating the moment a goal is scored. Technologies enabling real-time communication include WebSockets (full-duplex), Server-Sent Events (server-to-client only), WebRTC (peer-to-peer), and long polling (HTTP-based fallback).