Cookie Policy

AppNexus has created a technology platform (Platform) that our clients use to buy, sell, and deliver online advertising, including interest-based advertising, mostly through real-time bidding. The Platform is designed to use only non-PII, and AppNexus has contractual provisions that prohibit clients of the Platform from associating Platform cookies with PII. The Platform uses cookies to associate non-PII with browsers and devices, so that clients can then use the information to select ads for delivery by the Platform. For a detailed privacy statement that applies to the Platform, and information about how we use technologies other than cookies, see our Platform Privacy Policy. Below you will find information on AppNexus cookies, all of which are set on the domain. AppNexus has contractual provisions that prohibit clients of the Platform from setting, reading, writing, modifying, or deleting any cookie on an AppNexus domain. Except as noted in the table below, all of these cookies are set by the Platform.

Cookie Names



This cookie contains a unique randomly-generated value that enables the Platform to distinguish browsers and devices. It is matched against information – such as advertising interest segments and histories of ads shown in the browser or device – provided by clients or other third parties and stored on the Platform. This information is used by clients to select advertisements for delivery by the Platform, and to measure the performance of, and attribute payment for, those advertisements. In addition, to enable clients to use non-PII they collect outside the Platform or acquire from other third parties, this cookie is sometimes matched to clients’ or other third parties’ cookies that contain such non-PII. For more information about information collected and used on the Platform, see our platform privacy page.

uuid2 (opt out)

When a user opts out of having the Platform used to select ads based on online behavior, the unique value in uuid2 is deleted and replaced with the non-unique value “-1”. For more information about the Platform opt out, click here.


The sess cookie contains a single non-unique value: “1”. It is used by the Platform to test whether a browser is configured to accept cookies from AppNexus.


The icu cookie is used to select ads and limit the number of times a user sees a particular ad. It contains information such as the number of times an ad has been shown, how recently an ad has been shown, or how many total ads have been shown.


The anj cookie contains data denoting whether a cookie ID is synced with our partners. ID syncing enables our partners to use their data from outside the Platform on the Platform. (See our platform privacy page for more info.)


Cookies that start with token are helper cookies used as a security measure with industry opt-out pages. They contain a unique value only to verify the origin of opt-out requests.


Cookies that begin with acb have a value unique to a particular ad and are used to indicate to the Platform which ad to show and to record the fact that such ad was shown, for purposes such as billing and reporting.


This cookie is used for managing sessions of visitors to the website, which is intended for use by AppNexus employees. This cookie is used for administrative purposes. It is not set by the Platform or used for advertising purposes.