is it possible to send some json data with 401 error code example

Example 1: How to send JSON Web Token (JWT Token) as header with Postman and golang

func ProtectedEndpoint(w http.ResponseWriter, req *http.Request) {
    params := req.URL.Query()
    token, _ := jwt.Parse(params["token"][0], func(token *jwt.Token) (interface{}, error) {
        if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
            return nil, fmt.Errorf("There was an error")
        }
        return []byte("secret"), nil
    })
    if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
        var user User
        mapstructure.Decode(claims, &user)
        json.NewEncoder(w).Encode(user)
    } else {
        json.NewEncoder(w).Encode(Exception{Message: "Invalid authorization token"})
    }
}

Example 2: How to send JSON Web Token (JWT Token) as header with Postman and golang

func CreateTokenEndpoint(w http.ResponseWriter, req *http.Request) {
    var user User
    _ = json.NewDecoder(req.Body).Decode(&user)
    token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
        "username": user.Username,
    })
    tokenString, error := token.SignedString([]byte("secret"))
    if error != nil {
        fmt.Println(error)
    }
    json.NewEncoder(w).Encode(JwtToken{Token: tokenString})
}