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Cookies Stored by VWO

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VWO uses both persistent visitor-level and local storage cookies to identify all users, understand their behaviour, and track user journey on the website to deliver the best user experience. The cookies track the variation a user views and help serve the same variation to the user consistently, track goals completed by the user, and determine whether the user is part of a campaign.

VWO uses different cookies, each storing a different set of data. The cookies do not interfere with the loading or functioning of the page at all. The following cookies are used to collect visitor data when there is no test running on the page:

  • _vis_opt_test_cookie: This is a session (temporary) cookie generated to detect if the cookies are enabled on the browser of the user or not
  • _vis_opt_s: This cookie detects if the user is new or returning to a particular campaign
  • _vis_opt_out: This cookie indicates that the visitor is not a part of the campaign. This cookie is valid for 10 years

VWO uses the following cookies to track visitor-specific information and test data:

  • _vis_opt_exp_EXPERIMENT_ID_goal_GOAL_ID: This cookie is generated when a goal is made.

  • _vis_opt_exp_EXPERIMENT_ID_combi: This cookie is generated when users reach a particular combination. This makes sure that users see the same variation that they saw earlier when they visited the page.

  • _vis_opt_exp_EXPERIMENT_ID_exclude: This cookie is generated when a user is excluded from a campaign.

  • _vis_opt_exp_EXPERIMENT_ID_split: This cookie is generated during a Split URL test.

  • EXPERIMENT_ID refers to the ID of the campaign, and GOAL ID refers to the ID of the goal.

  • _vwo_uuid: This cookie generates a unique ID for every visitor and is used for the report segmentation feature in VWO. Also, this cookie allows you to view data in a more refined manner. If you have the campaign running on multiple domains, you will notice campaign-specific UUID values.

    In the _vis_opt_exp_EXPERIMENT_ID_combi cookie, the Control always has the value of 1, Variation #1 always has the value of 2, Variation #2 has the value of 3, and so on. Note that all the cookies except the _vis_opt_test_cookie and _vis_opt_out expire in 100 days.


Change Cookie Duration

VWO uses cookies to identify visitors and keep track of the variation they accessed. The default duration of a VWO cookie is 100 days. To change the duration, you can add the following JavaScript code snippet before the VWO tracking code on your webpage. 

<script type='text/javascript'>
_vis_opt_cookieDays = 1;
In this example, the cookie will last for a day only. Change the value from 1 to the number of days you want the cookie to be stored. Once the cookies are created, the duration cannot be altered.

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