VitalSentinel – SEO Extension

See what holds any page back: on-page SEO, indexability, Core Web Vitals and technical checks in one click, right in your browser.

See what holds any page back – in one click, right in your browser. VitalSentinel SEO Extension checks the page you are on for what stops it from ranking, loading fast or being understood by search engines and AI assistants. Every check runs on your device, and no account is needed. WHAT YOU GET ON EVERY PAGE Overview – HTTP status, indexability verdict, title, meta description, canonical, H1, word count, language and Core Web Vitals, with the issues that matter most and a link to each fix. On-page - Content: title and description length, heading outline with skipped levels, and a Google snippet preview with pixel-width truncation. - Structured data: JSON-LD and microdata with required and recommended properties for the main rich result types, parse errors, and links to the Rich Results Test and the Schema.org validator. - Social tags: Facebook, LinkedIn and X previews with every Open Graph and X tag. - Images: missing alt text and dimensions, oversized and lazy-loading issues, formats and the savings from resizing or WebP and AVIF. Crawl and index - Indexability: one verdict from the status code, meta robots, X-Robots-Tag, canonicals and robots.txt – also for pages opened with tracking parameters; sitemaps and whether the URL is listed; hreflang checks; raw HTML versus the rendered page. - Crawlers: robots.txt access for Googlebot, Bingbot and AI crawlers such as GPTBot, ClaudeBot and PerplexityBot, with the rule that decides it. - Links: internal, external, nofollow, sponsored and ugc links, with status checks on request. Performance - Core Web Vitals (LCP, INP, CLS, FCP, TTFB) measured for the real page load on your device, updating live. - The LCP element and layout shifts outlined on the page. - Render-blocking, uncompressed and short-cached files, page weight and the heaviest third-party hosts. - A one-click PageSpeed Insights link. Technical - HTTP headers: redirect chain, security headers, caching and compression. - Tech and tracking: CMS, framework, CDN, analytics, ads and consent tools; trackers and cookies set before consent; Consent Mode v2. - Accessibility: an axe-core audit grouped by impact. - AI readiness: llms.txt, AI crawler rules, content without JavaScript, structured data, semantic HTML and noai directives. Changed since your last visit – title, description, canonical, robots, H1, structured data and links compared with your previous visit to the same URL. Kept only in your browser, and you can turn it off. TOOLS - JavaScript switcher: turn JavaScript off for a site or a whole domain to see what crawlers see. Alt+Shift+Q or the right-click menu. - Domain Rating by Ahrefs on the toolbar icon. YOUR VITALSENTINEL DATA (OPTIONAL) Sign in with a VitalSentinel account and, on sites you monitor, the reports fill with the last 90 days of that exact page: Google Search Console clicks and queries, the Google index status, CrUX data for phone and desktop, and Web Analytics. Add any page to page monitoring in one click. The free plan covers one domain with every module, no credit card needed. PRIVACY The analysis itself runs in your browser. Domain Rating on the toolbar icon: while it is on, the extension sends the domain of each site you visit, never the full address, to VitalSentinel, which looks it up with Ahrefs. You can switch it off on the first screen or in Settings. Anonymous usage statistics and error counts are sent only if you turn them on. When you are signed in, a page's address is sent only for sites you monitor, without its tracking parameters. Offline mode stops every request except to the site you are viewing.