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Simple Web Server with Routes #

Build a Go web server without external dependencies — just the standard library.

Learn how to write simple, efficient web applications using Go. The time you invest in mastering the basics of Go’s standard library will yield greater returns than nearly any other technical investment you make.

In this short section, you'll create a basic web server using only the net/http package. We'll handle routing with http.NewServeMux(). By the end, you'll have a working server you can build on.

You don't need any external dependencies to build a production-ready web server in Go.

Changing Tires #

Imagine you're changing your car's wheels from winter to summer. You only need two tools:

You don't need a mechanic or a shop and you don't have to pay anyone.

It's the same with Go. The standard library is stable, fast, and all you need to build lightweight and reliable web servers.

Import the Package #

Here's the only import required to get started:

import "net/http"

Set Up a Router #

First, we create a new http.NewServeMux. It's a request multiplexer that matches incoming requests to registered handlers based on the request path. 

mux := http.NewServeMux()

We can now register routes on the mux using HandleFunc. This function takes two arguments:

  1. The method and route path (e.g. "GET /")
  2. A handler function that matches this signature: func(http.ResponseWriter, *http.Request)

Example

mux.HandleFunc("GET /{$}", func(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("Hello, World!"))
})

The /{$} route pattern matches only the / route and does not match paths like /foo, /bar or /foo/bar.

Complete Example #


package main

import (
    "errors"
    "fmt"
    "net/http"
    "os"
)

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("GET /{$}", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "Hello, World!")
    })

    srv := &http.Server{
        Addr:    fmt.Sprintf(":%d", 8080),
        Handler: mux,
    }

    err := srv.ListenAndServe()
    if !errors.Is(err, http.ErrServerClosed) {
        os.Exit(1)
    }
}
Simple Web Server in Go using a static route that returns "Hello, World!"

Try It with curl #

Once your server is running, you can test it using:

curl http://localhost:8080/

You should see this response:

Hello, World!

Contributions

Special thanks to Patrick Henry Winston his book Make It Clear was instrumental in shaping this article. Looking ahead, I’ll be focusing on two projects: Beago, a Go framework for building LLM-powered applications, and Vona, a minimalist and lightweight starter kit that that utilises Pico for beautiful plug-and-play landing page UI blocks.

Read more