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Álvaro García

Web app

Live

Free SEO Auditor

Analyse any public website: 70 checks across indexability, on-page, content, links, technical, structured data and Core Web Vitals, ordered by impact.

How I built it

Nothing is stored on the server. Crawls identify as AGSeoAuditor and respect robots.txt.

What it checks

Every check explains why it matters and how to fix it. Here they all are, by area.

Indexability17

  • The start URL does not respond correctly
  • robots.txt blocks the start URL
  • robots.txt blocks the whole site
  • No robots.txt
  • No XML sitemap found
  • Errors reading the sitemap
  • The sitemap lists non-indexable URLs
  • Sitemap URLs with no internal links
  • Pages set to noindex
  • Pages returning 4xx/5xx errors
  • Redirect chains
  • Missing canonical tag
  • Multiple canonical tags on one page
  • Canonical pointing to another URL
  • Canonical to an erroring or redirecting URL
  • hreflang issues
  • Non-existent URLs return 200 (soft 404)

On-page16

  • Pages without a <title>
  • Titles too short or too long
  • Duplicate titles
  • Multiple <title> tags
  • Pages without a meta description
  • Meta descriptions too short or too long
  • Duplicate meta descriptions
  • Pages without an H1
  • Multiple H1s on one page
  • Skipped heading levels
  • Missing lang attribute
  • Missing viewport meta
  • Character encoding not declared
  • Incomplete Open Graph
  • No Twitter/X Card
  • No favicon declared

Content10

  • Thin content
  • Low text-to-HTML ratio
  • Pages with identical content
  • Hard-to-read copy
  • Images without an alt attribute
  • Keyword missing from the title
  • Keyword missing from the H1
  • Keyword missing from the meta description
  • Keyword missing from the first 100 words
  • Keyword density too high

Links7

  • Broken internal links
  • Broken external links
  • Internal links that go through redirects
  • Links without accessible text
  • Generic anchor text
  • Internal links marked nofollow
  • Pages more than 3 clicks from the homepage

Technical10

  • The site does not use HTTPS
  • HTTP does not redirect to HTTPS
  • No HSTS header
  • Missing security headers
  • Mixed content (HTTP resources on HTTPS pages)
  • HTML served without compression
  • Slow server response (TTFB)
  • Very heavy HTML
  • Render-blocking resources
  • Images without dimensions

Structured data4

  • No structured data
  • JSON-LD with syntax errors
  • Incomplete structured data
  • The homepage does not declare its entity

Performance6

  • Poor mobile performance (Lighthouse < 50)
  • Mobile performance needs work (Lighthouse 50–89)
  • LCP above 2.5 s
  • CLS above 0.1
  • INP above 200 ms (real users)
  • High Total Blocking Time