When should you choose Server-Sent Events (SSE) over WebSockets?

Choose SSE for one-way server-to-client streaming (LLM tokens, live notifications, market price tickers). SSE runs over standard HTTP/2 multiplexing, supports built-in reconnection, and avoids WebSocket connection state overhead.

How do you handle client-side stream cancellation in SSE?

Use the Fetch API with an AbortController. When the user cancels generation or navigates away, call abortController.abort() to close the ReadableStream reader and cancel the server generation loop.

Stream Over HTTP First

mediumCore Concept

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GitHub, OpenAI, Perplexity, Stripe, Vercel

Problem statement

SSE is HTTP that does not end. Stream LLM tokens and one-way events before reaching for WebSockets — with Stop, buffering, and a clear when-not decision.

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Stream Over HTTP First

Problem statement

The full solution is part of HelloFrontend Pro

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