A GDPR cookie banner is a consent interface displayed to website visitors — typically on first visit — that informs them about the cookies and tracking technologies in use and requests their consent before non-essential cookies are set. Required under the EU’s General Data Protection Regulation (GDPR) and the ePrivacy Directive (the “Cookie Law”), the banner must give visitors a genuine choice: accepting and declining must be equally easy, and pre-ticked consent boxes are not lawful. For SEO, poorly implemented consent banners can cause problems: excessive layout shift affecting Core Web Vitals, blocking of Google Analytics data leading to gaps in reporting, and in some cases interfering with how Googlebot renders and indexes pages. Consent management platforms (CMPs) like Cookiebot and OneTrust are commonly used to handle compliance at scale.