Server-Sent Events (SSE) is a standard web technology that enables servers to push real-time updates to browser clients over a persistent HTTP connection using the text/event-stream content type. Unlike WebSockets, SSE provides unidirectional server-to-client streaming using familiar HTTP infrastructure, making it simpler to implement and deploy for scenarios like live notifications, dashboards, and progress updates. The key advantage is automatic reconnection: when a connection drops, the browser's EventSource API automatically attempts to reconnect, optionally resuming from the last event using the Last-Event-ID header. SSE works seamlessly with HTTP/2 multiplexing, eliminating the historical 6-connection-per-domain limitation that affected HTTP/1.1, and requires no special proxy configuration beyond disabling response buffering.