Server-Sent Events: The Forgotten Real-Time Workhorse

While everyone chases WebSockets for live features, Server-Sent Events (SSE) quietly powers GitHub’s activity feed, Stripe’s live logs, and ChatGPT’s streaming completions. One TCP connection, one header (text/event-stream), and zero external dependencies give you push-style updates in 12 lines of client code—no ws:// handshakes, no load-balancer sticky sessions, no extra open ports. Add automatic reconnection, ID-based resume, and built-in back-pressure, and SSE becomes the cheat code for dashboards, progress bars, and server logs that “just work” behind corporate proxies.

Yet SSE remains misunderstood: you can’t send binary blobs, you’re limited to six simultaneous streams per domain, and Safari still insists on waiting 300 ms before flushing the first byte. Work around these by base-64-encoding small payloads, sharding domains, and padding the initial payload with 2 kB of harmless comments. The result is a protocol that pings every browser—even IE11—without bundles, polyfills, or an extra 70 kB of JavaScript. Next time PMs scream “We need sockets,” smile and ship SSE in an afternoon; your future self (and your CDN bill) will thank you.