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Cookie statement

Welcome!

As stated in our Privacy Policy, Wikimedia believes strongly in the values of privacy and transparency. To that end, we’ve created this Cookie Statement as a clear reference guide to the use of cookies on Wikimedia Sites. This Cookie Statement explains how we use cookies (and other locally stored data technologies), how third-party cookies are used on Wikimedia Sites, and how you can manage your cookie options. For more information on our privacy practices, please visit our Privacy Policy.

The Wikimedia Foundation, the non-profit organization that hosts the Wikimedia Sites, actively collects some types of information with a variety of commonly-used technologies. These generally include tracking pixels, JavaScript, and a variety of "locally stored data" technologies, such as cookies and local storage.

Contents

1. What is a cookie?

A “cookie” is a tiny data file that we transfer onto your computer, mobile phone, or any other device that you use to access the Wikimedia Sites, generally used for authentication and tracking. Every cookie expires after a certain period of time, but that period varies depending on what the cookie is used for and how your browser is configured.

A “session” cookie is one that generally expires when you close your web browser or mobile application. A “persistent” cookie is one that remains in your device, even after you close your browser or mobile application. A persistent cookie expires according to the duration set by us (or when you delete it manually). Learn more on Wikipedia.

You may remove or disable cookies through your browser settings. For more information on how to manage your cookie options, please see Section 5 of this Cookie Statement below.

For more information on this and other key terms that may be relevant, please read through our Privacy Policy Glossary.

2. How do we use cookies?

We use the information we receive from cookies and other locally stored data to make your experience with the Wikimedia Sites safer and better, to gain a greater understanding of user preferences and interactions with the Wikimedia Sites, and to generally improve our services.

Cookies and other locally stored data, JavaScript, and tracking pixels help us do things like:

  • Provide you with a personalized experience, such as using cookies to know your language preference, to remember the user preferences you set so we can provide you with the customized look and feel that you want, and to tell you about interesting Wikimedia issues and events in your area.
  • Deliver more relevant content to you faster. For example, we may use local storage to store your most recently read articles directly on your device, so they can be retrieved quickly. Also, we may use cookies to learn about the topics searched so that we can optimize the search results we deliver to you.
  • Understand how you use the Wikimedia Sites, so that we know what works and what is useful. For example, we might use cookies to learn about the list of articles you are following on your watchlist so that we can recommend similar articles that you may be interested in.
  • Understand how you use the Wikimedia Sites across different devices, so that we can make our varied Wikimedia Sites more efficient and effective for you.
  • Make the Wikimedia Sites more convenient to use, such as by using cookies to maintain your session when you log in or to remember your username in the login field.

3. What types of cookies does Wikimedia use?

The cookies and other locally stored data technologies used by the Wikimedia Sites generally fall into the following categories:

  • Functionality: These cookies help the Wikimedia Sites work, including essential features like logging in.
  • Preferences: These cookies store your preferences, so that they can be remembered the next time you use the Wikimedia Sites.
  • Performance and Analysis: These cookies collect information about how you use the Wikimedia Sites, so that we can better understand how the Wikimedia Sites work and improve them for you and other users.
  • Third-Party: These cookies allow us to render services provided by third parties, such as “like” and “share” buttons. When a third party provides these kinds of services, they may require the use of a cookie in order to provide their services. (These kind of cookies would only be used with your permission.)

For more specific examples, we have provided the table below. But before you start reading, here is some background on Cookie Prefixes ("{$wgCookiePrefix}") you’ll find in the table.

Many of the Wikimedia Sites are technically separate sites – for example, French Wikipedia is different from English Wikipedia, and both are separate from French Wikibooks. As a result, we may set different cookies for different Wikimedia Sites. To help you (and your computer!) tell the Wikimedia Sites apart, each Wikimedia Site may set cookies that reflect their name. For example, enwikiUserName is a cookie that sets your username in “enwiki” - i.e., in English Wikipedia. frwikinewsUserName is a cookie that sets your username in “frwikinews” - i.e., in French Wikinews. We could list 800+ versions of UserName (one for each language and project), but instead this table will just have one entry for “UserName” - {$wgCookiePrefix}UserName. Wherever you see {$wgCookiePrefix}, that means you'll get one copy of the cookie for each of the Wikimedia Sites that you visit, and the name will be the “cookie prefix” (like enwiki, frwikinews, etc.) plus the rest of the name.

And now on to the table!

Name Expires Category What does it do?
centralauth_User 365 days, if the user chooses 'Keep me logged in'. Otherwise 30 days. Functionality Allows you to log in to many of the Wikimedia Projects using a single form, and stay logged in after providing your password.
CentralAuthAnon Either Local Storage, or a 1 day cookie Functionality Allows us to know that you are not currently logged in through our centralized account system.
centralauth_LoggedOut

LoggedOut

1 day from log out time Functionality Ensures recently logged out users do not see outdated cached content
centralauth_Session

{$wgCookiePrefix}Session

When user exits browser Functionality Manage sessions. Provides functionality such as logging in to Wikimedia Projects.
centralauth_Token

{$wgCookiePrefix}Token

365 days, if the user chooses 'Keep me logged in'. Otherwise omitted. Functionality Provides 'Keep me logged in' functionality.
centralnotice_bucket 7 days Performance and Analysis Helps us understand the effectiveness of notices provided to users through the CentralNotice extension. For more details, see https://www.mediawiki.org/wiki/Extension:CentralNotice
{$wgCookiePrefix}UserID, UserName 365 days, if the user chooses 'Keep me logged in'. Otherwise 30 days. Functionality Helps identify you to the wiki, and keeps you logged in.
{$wgCookiePrefix}forceHTTPS 30 days Functionality If you log in as https, and then later visit as http, this will cause you to redirect to https.
centralnotice_fundraising 1 year Functionality Allows us to stop showing banners to people once they’ve donated.
stopMobileRedirect 30 days Preferences Tells us not to redirect to the mobile site if you don't like that.
disableImages 30 days Preferences Allows you to disable images on the mobile site.
mfNearbyLastSearchResult Local Storage, not a cookie Functionality Helps us quickly show you nearby search results.
uls-preferences Local Storage, not a cookie Preferences Allows you to set preferences for the Universal Language Selector functionality.
langMap Local Storage, not a cookie Preferences Sets most highly prioritized languages for the language switcher on the mobile site.
mobile-language-tap-count Local Storage, not a cookie Preferences Allows us to know the effectiveness of the language switcher on the mobile site when the button is tapped.
mobile-betaoptin-token Local Storage, not a cookie Preferences Helps us to know on the mobile site if we've previously asked you to enroll in beta, so that we don't prompt you unnecessarily.
WMF-Last-Access 30 days Analytics Helps us calculate Unique devices accessing our site. See: https://blog.wikimedia.org/2016/03/30/unique-devices-dataset/
GeoIP Expires when user exits browser Functionality Helps us show you banners and other notices appropriate to your region, based on information from a GeoIP database
mwe-popups-enabled Local Storage, not a cookie Preferences Helps us to know if you have disabled Hovercards.
PopupsExperimentID Local Storage, not a cookie Preferences Helps us to know, while Hovercards experiments are running, whether to show you Hovercards.
ext.popups.core.previewCount Local Storage, not a cookie Performance and Analysis Helps us understand the effectiveness of Hovercards.
hidewatchlistmessage-[watchlistMessageId]
  • where watchlistMessageId is the Id of the message being hidden
28 days Preferences Allows a user to hide a watchlist message.
  • this cookie is on Persian Wikipedia (fa.wikipedia.org)
{$wgCookiePrefix}BlockID up to 24 hours Functionality Helps us enforce autoblocks, a system used to prevent vandalism and disruption

4. How do third parties use cookies on Wikimedia Sites?

Third-party cookies allow us to render services provided by third parties, such as “like” and “share” buttons. When a third party provides these kinds of services, they may require the use of a cookie in order to provide their services.

We will never use third-party cookies, unless we get your permission to do so. If you ever come across a third-party data collection tool that has not been authorized by you (such as one that may have been mistakenly placed by another user or administrator), please report it to us at privacy@wikimedia.org.

5. What are my cookie options?

While this is not a comprehensive list, here are some of the things that you can do to limit use of cookies and other locally stored data on your device. You can:

  • remove or disable specific locally stored data on your browser’s settings;
  • use a browser that can block third-party cookies; or
  • install a plug-in to block locally stored data, if one is available.

We believe this data collection helps improve your user experience, but you may remove or disable some or all locally stored data through your browser settings, depending on your browser. You can learn more about some options you have in our FAQ. While cookies and other locally stored data may not be necessary to use our sites, some features may not function properly if you disable locally stored data.

6. Where can I find more information?

Please read through our Privacy Policy for more information. If you have any further questions, contact privacy@wikimedia.org.

Thanks!

Please note that in the event of any differences in meaning or interpretation between the original English version of this document and a translation, the original English version takes precedence.