Does the MUID cookie need consent?

In the EU and the UK, yes. MUID is a marketing cookie and needs consent before it is set under the GDPR, the ePrivacy rules and PECR. Under the CCPA and CPRA, visitors can opt out of its use for cross-context behavioural advertising.

How long does the MUID cookie last?

MUID usually lasts 13 months. The exact lifetime depends on the site's settings and the version of the script that sets it.

Who sets the MUID cookie?

MUID is set by Microsoft. It is in the Marketing category.

How do I block or delete the MUID cookie?

Visitors can delete MUID in their browser's cookie settings. On your own website, a consent banner can keep the script that sets it waiting until the visitor accepts marketing cookies. Kukie.io's banner does this for known trackers by default, and for any other script you tag with its category.

Marketing

MUID cookie

Set by Microsoft.

What it does

Identifies unique web browsers visiting Microsoft sites.

Cookie name: MUID
Category: Marketing
Provider: Microsoft
Duration: 13 months
Data source: Kukie.io

Consent

Needed in the EU and the UK

MUID is in the Marketing category. In the EU and the UK, it needs the visitor's consent before it is set. Under California's CCPA, visitors can opt out of the sale or sharing of their personal information, including for cross-context behavioural advertising.

GDPR and ePrivacy (EU): Prior consent is needed before setting MUID. Advertising and tracking cookies are never covered by the strictly necessary exemption.
UK GDPR and PECR: Consent is needed before setting MUID.
CCPA and CPRA (California): Setting MUID for cross-context behavioural advertising counts as sharing personal information: offer a "Do Not Sell or Share My Personal Information" opt-out and honour the Global Privacy Control signal.

Managing MUID with a consent banner

A consent banner can keep the script that sets MUID waiting until the visitor accepts marketing cookies. Kukie.io's cookie scanner finds MUID and sorts it into a category. The banner holds back known trackers by default, and any other script you tag with its category waits too.

Learn more about script blocking

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