What is the __eoi cookie?
__eoi is an HTTP cookie set by Google, generally within Google Ads / DoubleClick services, when a page contains elements such as Google ads, remarketing tags, or Google Analytics integrations linked to Google Ads. Based on Google's public documentation, the name is associated with an internal identifier used by the advertising system, sometimes referred to as an "encrypted origin ID".
The cookie usually appears the first time a visitor's browser loads a Google Ads script or tag on the page, even without clicking on any ad.
What data it stores
__eoi stores an identifier generated by Google, used to correlate advertising requests and verify cookie functionality in the browser. The exact value format is not publicly documented in detail and may vary; based on available information, it does not contain directly identifying data such as a name or email address.
The value is sent to Google's servers (domains such as google.com or doubleclick.net) when the browser makes requests to Google's advertising services while browsing the site or other partner sites in the Google network.
What it is used for
For Google, __eoi supports the technical infrastructure of the Google Ads system — among other things, testing browser cookie support and correlating signals related to the origin of advertising requests, for ad delivery and measurement purposes.
For the site owner, this cookie's presence results from using Google Ads services (remarketing, conversion tracking, Google Analytics/Google Tag Manager integrations for advertising), indirectly contributing to the effectiveness of ad campaigns shown to site visitors.
Does it require consent?
__eoi is classified as a marketing/advertising cookie because it is used in the context of tracking and delivering targeted ads. Under GDPR and the ePrivacy Directive (transposed in Romania via Law 506/2004), this type of cookie requires the user's explicit, prior consent before being placed in the browser.
- The site owner must declare the cookie in the cookie policy under the "marketing" category.
- The script that generates __eoi (the Google Ads/DoubleClick tag) should only load after the user accepts marketing cookies.
- Refusing consent must not block access to the site's core content.
How to block or delete __eoi
A visitor can delete or block __eoi through browser settings (Chrome, Firefox, Edge, Safari), per-site cookie management, or ad-tracker blocking extensions. Google also offers an opt-out for personalized advertising via Google Ads Settings.
For site owners, the most reliable approach is technically blocking the script before consent: a CMP like CookieFix can automatically intercept Google Ads/DoubleClick tags and load them only after the visitor consents to the "marketing" category, preventing __eoi from being set prematurely.
Frequently asked questions
It's an HTTP cookie set by Google as part of Google Ads/DoubleClick services, used to test browser cookie support and functions related to the origin of advertising requests.
Yes, as a marketing/advertising cookie, it requires the visitor's prior, explicit consent under GDPR and ePrivacy.
It typically lasts about 6 months before expiring automatically from the browser.
By technically blocking the Google Ads/DoubleClick script before consent, using a CMP that loads the tag only after the visitor accepts the marketing category.