Familiarize yourself with the first-party and third-party cookies used by Optimizely X and Optimizely Classic
Understand when visitors are cookied
Optimizely uses persistent visitor-level cookies and localStorage to uniquely identify visitors, track their actions, and deliver consistent experiences across page loads. It sets a number of cookies, each storing a different set of data.
Use this article to understand the details of Optimizely's cookies. But take care not to directly reference the cookies and localStorage keys in code, as the specific data format and the cookies themselves may change over time and break your experiences. Instead, use the JavaScript API for Optimizely Classic or Optimizely X Web.
Optimizely uses both first and third-party cookies.
Please note that only two of the cookies below are used in Optimizely X (which is on a different technology stack from Optimizely Classic): optimizelyEndUserId and optimizelyRedirectData.
Important:
When developing experiences on your site, it's important to use the JavaScript API. Here are resources forOptimizely Classic and Optimizely X Web.
Take care not to reference the cookies and localStorage keys directly, as they may change at any time.
First-party cookies in Optimizely Classic
A first-party cookie is a cookie whose domain is set to the second-level domain (i.e. .yoursite.com) or a domain of your choice (per the setCookieDomain API). These cookies allow Optimizely to recognize your visitors as they travel through all subdomains of the cookie domain.
optimizelyBuckets
What: Records the Optimizely Classic variation that the visitor has seen for each experiment. This allows us to deliver a consistent experience on successive page loads.
Expiration: 10 years, or a period of your choice (per the setCookieExpiration API)
In a multivariate test, the variations a visitor sees are concatenated with an underscore, like this: {"experimentID":"section1variationID_section2variationID_section3variationID"}
What: Stores a visitor's unique Optimizely identifier, for both Optimizely Classic and Optimizely X Web. It's a combination of a timestamp and random number. No other information about you or your visitors is stored inside.
Example: oeu1383080393924r0.5047421827912331
Expiration: 10 years, or a period of your choice (per the setCookieExpiration API)
optimizelyPendingLogEvents
What: Used as a cache for a visitor's actions between tracking calls. This ensures that all events are efficiently tracked even if a visitor takes many actions in rapid succession. The cookie is wiped once the tracking call has been made.
Expiration: 15 seconds
optimizelyRedirect
What: After Optimizely Classic has executed a redirect experiment, stores the variation ID of the redirect experiment, so that Optimizely can pass it into integrated technology platforms along with the variation IDs that are active on the new page. This is necessary because the redirect experiment is usually inactive on the new page.
Expiration: 5 seconds
optimizelyReferrer
What: After Optimizely Classic has executed a redirect experiment, stores the document.referrer property from the original page, so that Optimizely can pass it into integrated technology platforms. This is how we avoid creating "self-referrals" in your third-party analytics.
Expiration: 5 seconds
optimizelySegments
What: Persists the visitor's Optimizely Classic segments: browser, campaign, mobile, source type, and any custom dimensions that you may have configured. This allows us to ensure persistence of segment membership, which improves the accuracy of segmented results.
Expiration: 10 years, or a period of your choice (per the setCookieExpiration API)
First-party cookies in Optimizely X
optimizelyEndUserId
What: Stores a visitor's unique Optimizely identifier, for both Optimizely Classic and Optimizely X Web. It's a combination of a timestamp and random number. No other information about you or your visitors is stored inside.
Example: oeu1383080393924r0.5047421827912331
Expiration: 10 years, or a period of your choice (per the setCookieExpiration API)
optimizelyRedirectData
What: After Optimizely X Web has executed a redirect experiment, stores various data from the original page so that Optimizely still has access to it on the new page.
Expiration: 5 seconds
Third-party cookies in Optimizely Classic
The domain for these cookies is {yourProjectId}.log.optimizely.com , thus classifying them as third-party cookies in relation to your page. They allow Optimizely to attribute your visitors' conversions on one of your domains to experiments/variations that they may have seen on another of your domains. Visitors are only tracked across domains that share the same Optimizely project ID.
This feature only works in browsers that recognize third-party cookies.
end_user_id
What: Stores a visitor's unique Optimizely identifier from a previous domain.
Expiration: 10 years
bucket_map
What: Stores a visitor's buckets from previous domains.
Expiration: 10 years
Third-party cookies in Optimizely X
Optimizely X sets a third-party cookie on the CDN targeting .optimizely.com.
What: Sets a cookie on the CDN for performance monitoring
Expiration: Expires when the session closes
Date created: 6/3/2016
Technical skills needed to implement this solution: Familiarity with browser developer tools
What's the problem?
3rd party cookies are not present within the Resources tab of the browser developer tools.
Solution:
Instead of using the Resource tab within the browser developer tools, you'll have to look into the Network panel for a request sent as part of a goal conversion.
Open up the browser developer tools --> Network
Fire off Optimizely request
Click on the request --> Headers --> Request Headers --> Look for the strings bucket_map and end_user_id
Alternatively, you can click on the Request --> Cookies and look for the strings bucket_map and end_user_id
Why is this information internal-only, and not customer facing?
This is not really information that needs to be digested by a large customer base. 3rd party cookies are more for cross-domain tracking (which works inconsistently), as well as reconciling user actions within our Backend.
localStorage
Optimizely stores data under the following keys in localStorage.
Keys set by Optimizely X Web
The following are keys set by Optimizely X Web Experimentation and Personalization, which is built on a different technology stack from Optimizely Classic.
Important:
When developing experiences on your site, it's important to use the JavaScript API. Here are resources forOptimizely Classic and Optimizely X Web.
Take care not to reference the cookies and localStorage keys directly, as they may change at any time.
What: Stores the visitor's values for various audience conditions. This is particularly important for "sticky" conditions like Ad Campaign, Source Type, and Referrer for which we need to rely on the first observed value.
optimizelyData$${visitorId}
optimizelyData$${visitorId}$$events
optimizelyData$${visitorId}$$event_queue
optimizelyData$${visitorId}$$layer_states
optimizelyData$${visitorId}$$session_state
optimizelyData$${visitorId}$$visitor_profile
optimizelyData$${visitorId}$$variation_map
These are keys that we used to set, in Classic and/or New Optimizely. The snippet no longer sets data under these keys, for visitors who originally received data for these keys, the snippet is slowly migrating their data over to the new keys.
Keys set by Optimizely Classic
The following are keys set by Optimizely Classic, which is built on a different technology stack from Optimizely X Web Experimentation and Personalization.
optimizely_data$$asyncInfo
What: Stores data that has been fetched from asynchronous data sources, such as data from Dynamic Customer Profiles. This gives us data that we can use immediately on later visits to your website.
What: Stores data from integration technology partners. This allows us to provide deeper client-side integrations.
Origins
Unlike cookie data, localStorage is scoped to a single "origin." An “origin” is a combination of a specific hostname, protocol, and port on your site. Two pages have the same origin if the protocol, port (if one is specified), and host are the same for both pages.
Here's an example of pages that don't have the same or different origins as https://shop.example.com:
You'll find that the documented localStorage keys are set on every domain that uses Optimizely X Web.
In order for Optimizely to recognize visitors across your pages and deliver consistent experiences, we replicate each visitor's data on all of your subdomains by routing it through another origin: https://a{yourAccountId}.cdn.optimizely.com/. Your visitors' data will be set on that origin as well, and on every page load with an Optimizely snippet on it, Optimizely makes an async call to this origin to sync this data. This will sync information across origin as well as across subdomains. Read more about tracking events across domains in Optimizely X Web.
Optimizely does not combine visitor data from multiple projects.
