What is the difference between WebSockets and Server-Sent Events (SSE)?
Answer
Server-Sent Events (SSE) is a simpler, unidirectional protocol for streaming data from server to client over a standard HTTP connection. WebSockets and SSE differ in: (1) Direction — WebSockets are full-duplex (both sides send); SSE is one-way (server to client only); (2) Protocol — SSE uses plain HTTP, WebSockets use their own protocol; (3) Browser support — SSE uses the native EventSource API; WebSockets use the WebSocket API; (4) Reconnection — SSE has built-in automatic reconnection; WebSockets require custom reconnection logic; (5) Complexity — SSE is simpler and works with standard HTTP infrastructure; (6) HTTP/2 — SSE multiplexes natively over HTTP/2; WebSocket has separate multiplexing. Use SSE for notifications, live feeds, and progress updates. Use WebSockets for interactive, bidirectional communication.