Temporary files installed by Yandex.Metrica

Yandex.Metrica provides depersonalized information about your site's traffic. The available statistics include the number of users, traffic sources, and user behavior on site pages. In order to count the site's users, Yandex.Metrica uses anonymous browser identifiers that are stored in cookies or in localStorage properties. These cookies and properties are set on the top-level domain, such as .example.com.

Cookie
Name Period of validity Description Domain where it is set
_ym_metrika_enabled 60 minutes Checks whether other Yandex.Metrica cookies are installed The domain where the tag is installed
_ym_isad 2 days Determines whether a user has ad blockers
_ym_uid 1 year Used for identifying site users
_ym_d Stores the date of the user's first site session
yabs-sid Until the session ends Session ID All Yandex.Metrica domains
_ym_debug Indicates that debug mode is active
_ym_mp2_substs Used for Target Call
_ym_visorc_* 30 minutes Allows Session Replay to function correctly
_ym_hostIndex 1 day Limits the number of requests
_ym_mp2_track 30 days Used for Target Call
i 1 year Used for identifying site users
yandexuid
usst Stores auxiliary information for syncing site user IDs between different Yandex domains
localStorage

These properties are set on the domain where the Yandex.Metrica tag is embedded.

Name Description
_ym<tag ID>_lastHit Used for specifying the time in order to get an accurate bounce rate
_ym<tag ID>_lsid Used for identifying site users
_ym<tag ID>_reqNum Used for determining the ordinal number of the request for the Yandex.Metrica tag in the browser
_ym_retryReqs Contains requests that the tag couldn't send to the server
zz Used for identifying site users