About the SEO Analyzer
The SEO Analyzer runs a comprehensive on-page audit against any public URL. It fetches the page server-side, parses the HTML, checks 40+ signals across meta tags, social previews, structured data, heading hierarchy, images, links, technical performance, security headers, robots.txt, sitemap, and international targeting — then returns an actionable fix list with a 0-100 score.
Every issue includes a concrete recommendation: what to add, where, and why it matters for search visibility. The report is server-generated (so it works for any origin, unlike browser-only tools), but no scan history is kept.
What the analyzer checks
🎯 Meta & head
<title> (length + presence), meta description (length + presence), canonical URL, robots meta directives, viewport, charset, HTML lang, favicon, Apple touch icon, and web manifest.
📱 Open Graph & Twitter Cards
All six Open Graph fields (title, description, image, url, type, site_name) plus the four Twitter Card fields (card, title, description, image). Missing fields are flagged with fix instructions.
🏷️ Structured data
JSON-LD schemas detected and listed by @type. Microdata (itemscope) and RDFa are reported. Structured data enables Google rich results — recipe cards, FAQ expandables, breadcrumb chains, star ratings — which increase click-through even without ranking changes.
📑 Content structure
Exactly one H1 per page, no skipped heading levels (H2 → H4 is a warning), plus full H1-H6 distribution. Also word count, text-to-HTML ratio, and reading time.
🖼️ Images
Total image count, images missing alt attributes (accessibility + SEO), and images missing width/height (Cumulative Layout Shift — a Core Web Vitals metric).
🔗 Links
Internal vs external link counts, nofollow ratio, empty anchor text, and mailto/tel presence.
⚡ Technical & performance
HTTP status, HTTPS enforcement, server response time, HTML payload size, HTTP protocol version, compression (Gzip/Brotli), and Cache-Control headers.
🛡️ Security headers
Strict-Transport-Security (HSTS), X-Frame-Options, X-Content-Type-Options, Content-Security-Policy, Referrer-Policy. Google factors HTTPS + security posture into ranking.
🤖 Robots.txt & sitemap
Verifies /robots.txt and /sitemap.xml exist, that the sitemap is referenced in robots.txt, and reports the total URL count in the sitemap.
🌐 International (hreflang)
Detects hreflang tags, validates ISO 639-1 / 3166-1 language codes, flags invalid formats — essential for multi-region sites.
How the 0-100 score works
Each check has a weight matching its SEO impact (title tag, HTTPS, H1 count carry more than favicon or manifest). Pass earns full weight, warn earns half, fail earns zero. The score is the weighted percentage; grade is A (90+), B (80+), C (70+), D (60+), F below 60.
Info-only checks (word count, heading distribution) never affect the score — they're context, not judgment.
Privacy & limits
The audit runs on our server (any tool that fetches a foreign URL must). Nothing is stored — the report is returned to your browser and discarded. Fetching is SSRF-guarded (private IPs blocked), rate-limited to 20 audits per minute per IP, capped at 2.5 MB per response, and times out at 15 seconds.
Is this a replacement for PageSpeed / Lighthouse?
No — different goals. Lighthouse simulates a real browser to measure Core Web Vitals (LCP, INP, CLS) and JavaScript execution. This tool audits the delivered HTML directly — faster, cheaper, and catches signals Lighthouse doesn't (structured data types, hreflang validity, security header specifics). Use both for the full picture.