Core Web Vitals
Core Web Vitals are three key user experience metrics that Google uses as ranking factors: Largest Contentful Paint (LCP, loading speed to 2.5 seconds), Interaction to Next Paint (INP, responsiveness under 200ms), and Cumulative Layout Shift (CLS, visual stability under 0.1). These metrics directly affect page rankings and are measured at the 75th percentile across real user data.
Definition
LCP measures the time it takes for the largest visible content element to load, targeting 2.5 seconds or less. INP measures the time from user input to the next visual update, targeting 200 milliseconds or less, replacing First Input Delay. CLS measures unexpected layout shifts during page load, targeting a score of 0.1 or less. Together these metrics quantify the page experience from a user's perspective. They are measured as percentiles across page visits, with Google targeting the 75th percentile as the threshold.
Improving Core Web Vitals requires optimizing JavaScript and CSS loading, deferring non-critical resources, and using browser caching. LCP improvements typically involve optimizing images, removing render-blocking resources, and using content delivery networks. INP improvements require reducing long JavaScript tasks and optimizing event handlers. CLS improvements focus on avoiding layout-shifting ads, images without dimensions, and embed content. Performance monitoring tools and browser APIs provide real-world data.
Why it matters for AI visibility
Page speed and responsiveness directly affect AI crawler efficiency and user experience for both humans and AI systems. A slow-loading page increases the time and resources required for AI crawlers to extract content. Poor responsiveness can cause incomplete rendering or missing information. AI systems prioritize fast-loading, stable pages as sources because they are more reliable to crawl and more likely to provide consistent user experience. Sites with poor Core Web Vitals are less likely to be selected as authoritative sources for AI citation.
Related terms
Page Speed
Page Speed is the time required for a web page to fully load and become interactive, measured through multiple metrics including Largest Contentful Paint (visual load), Time to Interactive (functional readiness), and Time to First Byte (server response). Slower pages negatively affect user experience, bounce rates, conversions, and search engine rankings across both traditional and AI search.
SEOPage Experience
Page Experience is a ranking signal comprising Core Web Vitals (speed, responsiveness, stability), mobile responsiveness, HTTPS security, safe browsing status, and absence of intrusive interstitials and aggressive ads. It holistically measures the user experience of visiting a web page and is a primary factor in Google's ranking algorithm reflecting user-centric quality.
SEOTechnical SEO Audit
A Technical SEO Audit is a comprehensive evaluation of a website's technical infrastructure including crawlability, indexability, performance, mobile experience, and structured data implementation. It identifies issues that prevent search engines and AI systems from discovering, crawling, and indexing content effectively, prioritizing findings by impact and effort to fix.
SEOMobile-First Indexing
Mobile-First Indexing is Google's practice of primarily using the mobile version of a website for crawling, indexing, and ranking, rather than desktop versions, reflecting the reality that most users access the web via mobile devices. This shift means mobile page performance, mobile content completeness, and mobile user experience are now primary ranking factors that directly impact visibility.