Building REST APIs with Go

Building a REST API in Go doesn't require a heavy framework. The standard library gets you surprisingly far, and a small router on top keeps things clean without hiding what's happening.

Why the standard library goes a long way

net/http in Go 1.22+ supports method-based routing and path parameters out of the box. For many services, that's enough.

package main

import (
    "encoding/json"
    "net/http"
)

type User struct {
    ID   string `json:"id"`
    Name string `json:"name"`
}

func main() {
    mux := http.NewServeMux()

    mux.HandleFunc("GET /users/{id}", func(w http.ResponseWriter, r *http.Request) {
        id := r.PathValue("id")
        json.NewEncoder(w).Encode(User{ID: id, Name: "Alain"})
    })

    http.ListenAndServe(":8080", mux)
}

Middleware as plain functions

Middleware is just func(http.Handler) http.Handler. No magic, no adapters.

func logging(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        log.Printf("%s %s", r.Method, r.URL.Path)
        next.ServeHTTP(w, r)
    })
}

Keep handlers thin

Handlers should decode, delegate to a service, and encode. Business logic belongs elsewhere — it makes testing far easier.

That's the core of a maintainable API in Go: small pieces, explicit wiring, no surprises.