What is the UserMatchHistory cookie?
UserMatchHistory is an HTTP cookie set by LinkedIn (Microsoft), primarily used by LinkedIn Ads for conversion tracking and cross-device/cross-site user matching.
It appears on a website when the site integrates the LinkedIn Insight Tag (LinkedIn's conversion tracking and retargeting script) or other LinkedIn widgets that load resources from linkedin.com. It is generally set on the linkedin.com domain rather than the host site's own domain.
What data it stores
The cookie stores an identifier tied to ad conversion tracking activity, used by LinkedIn to correlate visits on partner sites with a LinkedIn user account or profile. LinkedIn does not publicly document the exact value format.
Data collected through this cookie is sent to LinkedIn/Microsoft servers and may be used for conversion reporting, campaign optimization, and potentially shared across other Microsoft group services, per LinkedIn's privacy policy.
What it is used for
For LinkedIn, the cookie helps measure the effectiveness of LinkedIn Ads campaigns by linking ad impressions or clicks to later actions a user takes on partner websites.
For the site owner, this cookie enables conversion reporting from LinkedIn campaigns and, in some cases, building retargeting audiences based on site visitors.
Does it require consent?
UserMatchHistory is classified as a marketing/advertising cookie. Under the ePrivacy Directive (implemented in Romania via Law 506/2004) and the GDPR, this type of cookie cannot be set before the visitor gives explicit consent.
- The site owner must list the cookie in the cookie policy, including its category, provider, and duration.
- The LinkedIn Insight Tag script should only load after consent, not preemptively.
- Refusing consent must not block access to the site's core content.
How to block or delete UserMatchHistory
A visitor can delete or block this cookie through browser settings (Chrome, Firefox, Edge, Safari) under per-site cookie management, or by using ad-tracker blocking extensions.
For site owners, the recommended approach is a consent management platform (CMP) such as CookieFix, which automatically blocks the LinkedIn Insight Tag script from executing until the visitor accepts the marketing category, preventing the cookie from being set prematurely.
Frequently asked questions
It's a marketing cookie used by LinkedIn Ads for conversion tracking and matching users across websites and the LinkedIn platform.
It typically has a 30-day duration from when it is set or last updated.
No, it's a marketing/advertising cookie and requires prior user consent under GDPR and Romania's Law 506/2004.
By using a CMP that delays loading the LinkedIn Insight Tag until the visitor accepts the marketing category, such as CookieFix.