Streaming at Scale: Engineering an SSE Pipeline
Token streaming is the default for LLM traffic. Here is how we engineered our SSE pipeline to keep bytes flowing under load, without breaking the experience.
Sofia García · Product ManagerMay 2, 2026 · 9 min read
Streaming is the hot path
Users judge latency by time-to-first-token, so the gateway is built around streaming: connections are long-lived, buffering is minimal, and backpressure is handled explicitly at every hop.
Backpressure without stalling
Slow clients must not stall fast upstreams. We decouple upstream consumption from client delivery with bounded buffers, so one slow reader never blocks the pipeline for everyone else.
Observable streams
Every stream carries a request ID, and metrics capture token throughput and flush latency in real time. When something feels slow, we can point at the exact hop that delayed it.