What exactly are you trying to accomplish? If you set a cookie - without specifying a domain - on https://foo.bar.com, that cookie will only be active for foo.bar.com. Are you wanting to make the cookie active for all of bar.com? If so, you can pass the domain to the set() method. There doesn't appear to be a global setting, but if you want one, it should be pretty straightforward to write your own class that extends Phalcon\Http\Response\Cookies and overrides set() - injecting the domain you want in a call to parent::set().