Knowledge base Understand every SEO check — what it is, an example, and how to fix it. Internal pages Invalid SSL certificate Mixed content Non-200 HTTP status Site not served over HTTPS Indexability Canonical points to another URL Invalid canonical URL Missing canonical tag Noindex on live page Links Broken internal link Low internal links Orphan page Page too deep Redirects 302 redirect 3XX redirect HTTP is not redirected to HTTPS HTTP to HTTPS redirect Long redirect chain Content Duplicate content Duplicate meta description Duplicate title Images missing alt text Incomplete Open Graph tags Meta description too long Missing <title> tag Missing H1 Missing meta description Missing structured data Multiple H1s Near-duplicate content Thin content Title too long Title too short Images Image file too large Page has broken image Page has redirected image JavaScript JavaScript file too large Page has broken JavaScript Page has redirected JavaScript CSS CSS file too large Page has broken CSS Page has redirected CSS Localization Invalid hreflang values Missing hreflang x-default Performance Heavy page Poor CLS Poor INP Poor LCP Privacy-friendly analytics & real-user Core Web Vitals Eco Heavy page footprint Response not compressed Too many requests Generative Engine (GEO) Missing author or attribution Missing freshness dates Answer Engine (AEO) No question-style headings Q&A content without FAQ schema Sitemaps Missing sitemap.xml Sitemap contains no URLs robots.txt does not reference a sitemap Other Missing robots.txt