procedure TForm3.btnSendPostRequestClick(Sender: TObject);
var
  LFormData: TStringList;
  LResp: IHTTPResponse;
begin
  LFormData := TStringList.Create(true);
  try
    LFormData.Values['first_name'] := 'Daniele';
    LFormData.Values['last_name'] := 'Teti';
    LFormData.Values['work_phone_number'] := '789-9876542';
    LFormData.Values['mobile_phone_number'] := '555-7854216';
    LFormData.Values['email'] := 'd.teti@bittime.it';
    LResp := NetHTTPClient1.Post('http://localhost:8080/saveperson', LFormData);
    Memo1.Lines.Text := LResp.ContentAsString();
  finally
    LFormData.Free;
  end;
end;