Why architecture matters here

Streaming fails on proxies that buffer, missing cancellation, and no idle timeout. Architecture matters because HTTP + serving + client combine.

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The architecture: every piece explained

The top strip is the primary path. Client opens SSE. Serving engine token-by-token. Chunked encoding flushes tokens. UI render streams.

The middle row is control. Cancellation. Rate + throttling. Structured output stream. Tool call events.

The lower rows are ops. Timeouts. Observability. Ops — proxies + LB + retry.

LLM streaming output — SSE + token cadence + partials + cancellation + ratewords appear as they're generatedClientopens SSE / WSServing enginetoken-by-tokenChunked encodingflush tokensUI renderstreaming textCancellationclient disconnectRate + throttlingserver + clientStructured output streamJSON tokensTool call eventstypedTimeoutsidle + totalObservabilityTTFT + tailOps — proxies + LB + retry semanticsabortpacestreamtypeboundmeasuremeasureoperateoperate
LLM streaming output pipeline.
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End-to-end flow

End-to-end: user asks. Client opens SSE. Server generates + flushes each token. UI appends. User closes tab; server detects; cancellation aborts generation. Tool call event streamed as typed message. Metrics show TTFT p50 250ms.