Third-Party Cookies vs. First-Party Cookies

Cookies are small files stored locally on your computer that are designed to hold data specific to a particular client and site. Cookies can be accessed by a server or a client computer. Cookies allow the server to deliver a page tailored to a particular site visitor, or the page itself can contain some script that is aware of the data in the cookie to carry information from one visit to the site (or related site) to the next.

For example, when you log into a site, you remain logged in on multiple pages on the same domain. This is because your logged-in state has been stored in a cookie.

Third-Party Cookies

All cookies have an owner that lets you know who the cookie belongs to. The owner is the domain specified in the cookie. In the third-party cookie, the word party refers to the domain specified in the cookie. A third-party cookie is a cookie set by (and on) a domain name that isn't the domain name that appears in the browser address bar.

Consider the following example:

  • If you visit and the domain of the cookie placed on your computer is, then this is a first-party cookie.
  • If, however, you visit and the cookie placed on your computer is, then this is a third-party cookie.

How Does This Affect Monetate?

The Monetate cookie is set as a first-party cookie, and it should be issued to the full domain name for the site that Monetate is installed on. Therefore, all first-party cookies—including Monetate IDs that are stored in a first-party cookie in the client's domain—are unaffected.

Exception: Preview Mode

Browsers configured to block third-party cookies prevent Monetate's Preview functionality. This setting doesn't impact experiences live in production since the mt.v cookie used to serve content in production is a first-party cookie. The cookie used for Preview functionality, however, is served through the Monetate user interface as a third-party. To work around this behavior, either add the Monetate Preview cookie to the safelist on your domains, or disable the third-party cookie blocking in your browser.