Performance cookies (also called measurement cookies) collect anonymized data about how visitors interact with a website — which pages they visit, how long they stay, which links they click, and where they encounter errors. Unlike marketing cookies, they are not used for behavioral targeting; their purpose is to help site owners improve website functionality. Common providers include Adobe Analytics, Hotjar, and Crazy Egg. Despite their non-targeting purpose, performance cookies require GDPR opt-in consent because they access the user's device and process personal data such as IP addresses. The strictly necessary cookie exemption does not apply to performance cookies.