How do you build a basic HTTP server using only the standard library?

Question

Accepted Answer

package main

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

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

mux.HandleFunc("GET /users/{id}", getUserHandler)
    mux.HandleFunc("POST /users", createUserHandler)
    mux.HandleFunc("GET /health", healthHandler)

srv := &http.Server{
        Addr:         ":8080",
        Handler:      mux,
        ReadTimeout:  5 * time.Second,
        WriteTimeout: 10 * time.Second,
        IdleTimeout:  120 * time.Second,
    }

log.Println("server starting on :8080")
    if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
        log.Fatalf("server error: %v", err)
    }
}

func getUserHandler(w http.ResponseWriter, r *http.Request) {
    id := r.PathValue("id") // Go 1.22+ path parameters
    user := &User{ID: id, Name: "Alice"}

w.Header().Set("Content-Type", "application/json")
    w.WriteHeader(http.StatusOK)
    json.NewEncoder(w).Encode(user)
}

func healthHandler(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(http.StatusOK)
    w.Write([]byte(`{"status":"ok"}`))
} Always set ReadTimeout, WriteTimeout, IdleTimeout — defaults are zero (no timeout = DoS vulnerability) Go 1.22 adds method and path parameter support to ServeMux: GET /users/{id} Use http.NewServeMux() not the default mux to avoid global state in tests Wrap with middleware for logging, auth, and panic recovery before registering with the server For HTTP/2 and TLS: use srv.ListenAndServeTLS(certFile, keyFile)

How do you build a basic HTTP server using only the standard library?

The net/http package provides everything needed for a production-ready HTTP server. Use a custom http.ServeMux and configure server timeouts to prevent slow-client attacks.

How do you build a basic HTTP server using only the standard library?

The net/http package provides everything needed for a production-ready HTTP server. Use a custom http.ServeMux and configure server timeouts to prevent slow-client attacks.

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