📡 Real-Time Streaming Reference

Master Server-Sent Events
& Real-Time Streaming

The definitive technical reference for full-stack engineers building real-time systems. From SSE protocol internals and the event stream format, to backend generation in Node.js, Python, and Go with Redis fan-out and backpressure control, to frontend consumption with React and Vue EventSource hooks.

SSE Protocol Fundamentals Backend Stream Generation Frontend Consumption

What You'll Find Here

Server-Sent Events (SSE) provide a standardised, unidirectional HTTP streaming protocol purpose-built for server-to-client real-time communication. Unlike WebSockets or long-polling, SSE operates over plain HTTP/1.1 or HTTP/2, requires no protocol upgrade, and delivers automatic reconnection with cursor tracking out of the box through the browser's native EventSource API.

This site covers the full production stack across three sections. SSE protocol fundamentals dig into the event stream format, event IDs and retry, security headers, and cross-browser support. Backend stream generation covers serving SSE from Node.js, Python/FastAPI, and Go — with connection pooling, buffer management, Redis pub/sub fan-out, rate limiting and backpressure, and idempotent event IDs. Frontend consumption covers React and Vue EventSource hooks, state-management integration, reconnection UX, and mobile background-tab handling.

Whether you're building telemetry dashboards, notification pipelines, live data feeds, or migrating from polling to persistent streams, every guide provides production-grade code examples, edge case mitigations, and actionable deployment directives.

Browse by Section

Three comprehensive sections covering the full SSE stack — from protocol internals to backend generation and frontend consumption.

SSE Protocol Fundamentals Protocol internals, event stream format, security headers, retry mechanisms, and cross-browser support. Backend Stream Generation Node.js, Python, and Go streaming, connection pooling, buffer management, Redis fan-out, rate limiting, and idempotent event IDs. Frontend Consumption Patterns EventSource hooks for React and Vue, state-management integration, reconnection UX, and mobile background-tab handling.

All Topics

Browser Support & Polyfill Strategies EventSource support matrix, polyfill options, fetch+ReadableStream fallbacks, and tiered degradation patterns for production SSE deployments. Event ID & Retry Mechanism Design How SSE event IDs and retry directives enable deterministic stream resumption: wire format, server-side cursors, backoff design, and production edge cases. Security Headers for Event Streams Complete guide to HTTP security headers for SSE endpoints: CORS, CSP, auth, X-Accel-Buffering, and production hardening for long-lived streams. SSE vs WebSockets vs HTTP Polling Compare SSE, WebSockets, and HTTP polling on latency, connection overhead, directionality, proxy compatibility, and scaling to pick the right transport. Understanding the Event Stream Format Complete field-by-field reference for the text/event-stream wire format: data, event, id, retry, comments, framing rules, and parser edge cases. Buffer Management & Chunked Transfer Encoding Master HTTP chunked transfer encoding, flush timing, watermark tuning, and proxy buffering bypass for production SSE streams across Node.js, Python, and Go. Connection Pooling for SSE Servers How to manage thousands of long-lived SSE connections: FD limits, worker tuning, pooled sockets, heartbeats, and graceful drain under load. Go Streaming Patterns for SSE Idiomatic Go SSE using http.Flusher, goroutines, channels, context cancellation, and graceful shutdown — with production-ready patterns. HTTP Keep-Alive & Connection Lifecycle How HTTP Keep-Alive, TCP keepalives, heartbeats, and teardown interact for long-lived SSE streams — config, edge cases, and production ops. Idempotent Event ID Generation Assign collision-free, monotonic IDs to SSE events so clients can resume streams after disconnection without duplicates or missed events. Node.js Streaming Architecture Basics Build reliable SSE endpoints in Node.js: headers, res.write, flush, heartbeats, backpressure, disconnect cleanup, and production ops. Python FastAPI SSE Implementation Guide Ship production SSE endpoints with FastAPI: StreamingResponse, async generators, sse-starlette, ASGI tuning, proxy buffering, and scale considerations. Rate Limiting & Backpressure Handling Token-bucket rate limiting, slow-consumer backpressure, and drop policies for SSE servers — Node.js, Go, and Python patterns with production ops. Redis Pub/Sub Fan-Out for SSE Decouple SSE producers from connections using Redis pub/sub. Multi-node broadcast, channel design, at-least-once delivery, and backpressure strategies. Error Handling & Reconnection UX Implement SSE reconnection with exponential backoff, surface connection state to users, handle stale data, and design graceful degradation for unreliable networks. Mobile & Background-Tab Handling Manage SSE connections across Page Visibility changes, mobile tab suspension, battery constraints, and resume with Last-Event-ID to avoid event loss. React EventSource Hooks & State Encapsulate EventSource in React hooks for lifecycle-safe SSE: cleanup, re-render control, error handling, and concurrent-mode compatibility. State-Management Integration for SSE Feed SSE events into Redux, Pinia, and Zustand: action dispatch, normalization, optimistic updates, deduplication, and backpressure patterns. Vue EventSource Composables Build reactive Vue 3 composables for SSE: useEventSource with ref-based state, onUnmounted cleanup, typed events, and exponential-backoff reconnection.