A simple api gateway from scratch written in golang

Building an API Gateway From Scratch in Go API gateways are one of those infrastructure components that feel intimidating from the outside. You know they handle auth, routing, rate limiting, but the internals are a black box. I decided to fix that by building one from scratch in Go, using nothing but the standard library's net/http . No frameworks. Just code. This post walks through the design of simple-api-gateway : what it does, how it's structured, and the key implementation decisions along the way. The Core Idea: A Gateway is Just a Middleware Chain Before diving in, it's worth naming the central insight: an API gateway is fundamentally a configurable http.Handler . Every feature, auth, rate limiting, tracing, is just middleware wrapped around a reverse proxy. In Go, that pattern looks like this: type Middleware func ( http . Handler ) http . Handler A middleware takes a handler and returns a new handler that does something before or after calling the next one. Chain enough of thes