package main import ( "encoding/json" "log" "net/http" ) type v struct { V string `json:"version"` } func main() { http.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) { w.Header().Set("Content-Type", "application/json") r := v{"v0.0.1"} if err := json.NewEncoder(w).Encode(r); err != nil { log.Printf("json: %+v", err) } }) if err := http.ListenAndServe(":8080", nil); err != nil { log.Fatalf("listen and serve: %v", err) } }