Streaming LLM responses to the browser in Go (Server-Sent Events)

The biggest UX mistake in LLM-powered web apps is waiting for the complete response before sending anything. On a 400-token answer at typical generation speeds, that's 4–8 seconds of staring at a spinner. With streaming, the user sees the first word in under a second and reads along as the model generates. This tutorial shows you exactly how to implement token-by-token streaming from an LLM API to the browser using Server-Sent Events (SSE) in Go Fiber.

Why SSE and not WebSockets?

WebSockets are bidirectional. For LLM streaming, you don't need that — you send one request, the server pushes tokens back. SSE is:

Unidirectional (server → client), which fits the problem exactly

A plain HTTP/1.1 connection with text/event-stream content type