end_point.go

package main

import (
	"net/http"
	"github.com/mrkplt/end_point/models"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
  	w.Header().Set("Content-Type", "application/json")
	  w.Write(models.User{FirstName: "Mark"}.Json())
	})
	http.ListenAndServe(":8080", nil)
}

user.go

package models

import "encoding/json"

type User struct {
  FirstName string `json:"first_name"`
}

func (u User) Json() (r []byte) {
  r, _ = json.Marshal(&u)
  return r
}

that's pretty nice - i'll have to play around with it.