Server-Sent Events (SSE): ментальная модель

SSE — one-way UTF-8 text stream over never-closing HTTP response. EventSource parses wire format, auto-reconnects, resumes from last event ID.

Разбор

Not new protocol — ordinary GET with Content-Type: text/event-stream, body never ends. Server flushes text frames; client reads as they arrive.

Premium in one package: line-based format + native EventSource with reconnect and «resume from where I was». WebSocket = raw duplex, you build all that. SSE = 80% case in ~5 lines.

Client ──GET /stream (Accept: text/event-stream)──▶ Server
Client ◀───────────── data: {...}

 ─────────────  (kept open,
Client ◀───────────── data: {...}

 ─────────────   server pushes
Client ◀───────────── data: {...}

 ─────────────   whenever it likes)

Итог

SSE when server talks, client listens — simpler than WebSocket for feeds, notifications, live logs.