Technical Seo Audit

Technical SEO Audit

Deep technical SEO analysis: crawlability, indexation, Core Web Vitals, site architecture, and performance.

Install

git clone https://github.com/thatrebeccarae/claude-marketing.git && cp -r claude-marketing/skills/technical-seo-audit ~/.claude/skills/

How this differs from seo-content-writer: The seo-content-writer skill focuses on content optimization — keywords, readability, meta tags, heading structure. This skill audits the technical foundation — can search engines crawl, render, and index your site correctly?

Audit Framework

Phase 1: Crawlability & Indexation

robots.txt Analysis

• Verify file exists at /robots.txt
• Check for unintentional blocks (Disallow: / on production)
• Validate sitemap reference
• Review AI crawler directives (GPTBot, ClaudeBot, PerplexityBot)

XML Sitemap Audit

• Validate sitemap format (XML schema compliance)
• Check for 404, 301, or 5xx URLs in sitemap
• Verify lastmod dates are accurate (not all the same date)
• Confirm sitemap is referenced in robots.txt
• Check sitemap size (under 50MB / 50,000 URLs per file)
• For large sites: verify sitemap index file structure

Indexation Health

• Compare indexed pages (site:domain.com) vs expected pages
• Identify index bloat (thin, duplicate, or low-value pages indexed)
• Check for noindex tags on important pages
• Review Google Search Console coverage report patterns
• Identify orphan pages (in sitemap but no internal links)

Crawl Budget Optimization

• Identify crawl traps (infinite pagination, calendar URLs, faceted navigation)
• Check crawl depth (critical pages should be within 3 clicks)
• Review log files for crawler behavior patterns
• Identify wasted crawl budget on low-value URLs

Phase 2: Site Architecture & Internal Linking

URL Structure

• Consistent URL patterns (lowercase, hyphens, no trailing slashes OR consistent trailing slashes)
• Logical hierarchy reflecting content taxonomy
• No URL parameters where clean URLs are possible
• Proper handling of pagination (rel=next/prev or load-more)

Internal Link Analysis

• PageRank flow: are high-authority pages linking to important content?
• Orphan page detection (pages with zero internal links)
• Broken internal links (404s)
• Anchor text distribution (relevant, varied, not over-optimized)
• Link depth audit (pages more than 3 clicks from homepage)

Navigation & Hierarchy

• Breadcrumb implementation (with BreadcrumbList schema)
• Navigation depth (flatten deep hierarchies)
• Footer link optimization
• Faceted navigation handling (noindex, canonical, or robots)

Phase 3: Core Web Vitals & Performance

Largest Contentful Paint (LCP) — Target: <2.5s

• Identify LCP element (usually hero image or H1)
• Check image optimization (format, compression, dimensions)
• Verify preload for LCP resources
• Check server response time (TTFB)
• Review render-blocking resources

Interaction to Next Paint (INP) — Target: <200ms

• Identify long tasks blocking the main thread
• Review JavaScript execution time
• Check event handler performance
• Evaluate third-party script impact

Cumulative Layout Shift (CLS) — Target: <0.1

• Check for images/embeds without dimensions
• Review dynamic content injection above the fold
• Verify font loading strategy (font-display: swap or optional)
• Check ad slot reservations

Performance Checklist

• [ ] Images: WebP/AVIF format, responsive srcset, lazy loading below fold
• [ ] CSS: Critical CSS inlined, non-critical deferred
• [ ] JavaScript: Deferred or async loading, code splitting
• [ ] Fonts: Preloaded, font-display set, subset if possible
• [ ] Server: HTTP/2 or HTTP/3, compression (Brotli > gzip), CDN
• [ ] Caching: Proper cache-control headers, service worker for repeat visits

Phase 4: On-Page Technical Elements

Meta Tags

• Title tags: unique, 50-60 characters, primary keyword near start
• Meta descriptions: unique, 150-160 characters, include CTA
• Viewport meta tag present
• Charset declaration (UTF-8)
• No conflicting meta robots directives

Canonical Tags

• Every page has a canonical tag (self-referencing or pointing to canonical version)
• Canonical tags are absolute URLs (not relative)
• No canonical chains (A -> B -> C)
• Canonicals consistent with internal links, sitemaps, and hreflang
• HTTP pages canonical to HTTPS versions

Heading Hierarchy

• Single H1 per page
• Logical H1 > H2 > H3 nesting (no skipped levels)
• H1 contains primary keyword
• Headings are descriptive (not "Introduction" or "Section 1")

Structured Data

• Validate with Google Rich Results Test
• Check for errors/warnings in Search Console
• Verify required fields per schema type
• Cross-reference with aeo-geo-optimizer and schema-markup-generator skills

Phase 5: HTTPS & Security

• SSL certificate valid and not expiring soon
• All resources loaded over HTTPS (no mixed content)
• HTTP to HTTPS redirect chain (single 301, not chain)
• HSTS header present
• Security headers (X-Content-Type-Options, X-Frame-Options, CSP)

Phase 6: International & Multi-Language (if applicable)

• Hreflang implementation (correct language/region codes)
• Hreflang reciprocal links (A points to B, B points to A)
• X-default tag for fallback
• Language-specific sitemaps
• Content localization quality (not just translation)

Phase 7: Mobile Optimization

• Mobile-first indexing readiness (same content on mobile and desktop)
• Touch targets sized appropriately (48x48px minimum)
• No horizontal scrolling
• Readable font sizes without zooming (16px base minimum)
• Mobile page speed (test on 3G connection profile)

Audit Report Structure

Executive Summary

• Overall technical health score (0-100)
• Critical issues count (blocking indexation/ranking)
• High-priority issues count (impacting performance)
• Quick wins count (easy fixes, high impact)

Issue Classification

Per-Issue Format

**Issue:** [What is wrong]
**Impact:** [How it affects SEO performance]
**Pages Affected:** [Count or list]
**Fix:** [Specific remediation steps]
**Validation:** [How to verify the fix worked]

Common Tools & Commands

# Check robots.txt
curl -s https://example.com/robots.txt

# Check HTTP headers
curl -I https://example.com

# Check redirect chain
curl -sIL https://example.com 2>&1 | grep -E "HTTP/|Location:"

# Validate sitemap
curl -s https://example.com/sitemap.xml | head -20

# Check page speed (via PageSpeed Insights API)
curl "https://www.googleapis.com/pagespeedonline/v5/runPagespeed?url=https://example.com&strategy=mobile"

# Check DNS resolution
dig example.com +short

# Check SSL certificate
echo | openssl s_client -servername example.com -connect example.com:443 2>/dev/null | openssl x509 -noout -dates

Benchmarks

Integration with Other Skills

• aeo-geo-optimizer — Layer AI search optimization after technical foundation is solid
• schema-markup-generator — Generate structured data identified as missing during audit
• google-analytics — Correlate technical issues with traffic impact
• pro-report-builder — Generate professional audit deliverable from findings

Technical SEO Audit — Examples

Example 1: Full Site Technical Audit

Prompt

Run a full technical SEO audit on our e-commerce site. We have about 5,000 pages and have noticed a decline in organic traffic over the last 3 months.

What the skill does

1. Crawlability check: Reviews robots.txt, XML sitemap (finds 2,300 URLs returning 404), checks crawl depth (product pages are 5+ clicks deep) 2. Indexation analysis: Compares 5,000 expected pages vs 3,200 indexed — finds 1,800 pages with noindex tags from a staging migration 3. Core Web Vitals: LCP at 4.2s (poor) due to unoptimized hero images, CLS at 0.18 (needs work) from ads without reserved space 4. Architecture: Identifies 340 orphan product pages with zero internal links 5. Produces audit report with 3 critical, 8 high, 12 medium issues and prioritized fix timeline

---

Example 2: Core Web Vitals Fix

Prompt

Our LCP is 4.8 seconds on mobile. Help me diagnose and fix it.

What the skill does

1. Checks TTFB (620ms — acceptable) 2. Identifies LCP element: 2.4MB uncompressed PNG hero image 3. Finds 3 render-blocking CSS files and 2 synchronous JS bundles 4. Prescribes fixes: convert hero to WebP (saves 1.8MB), add preload hint, defer non-critical CSS, async JS loading 5. Estimates improvement: LCP from 4.8s to ~1.8s

---

Example 3: Post-Migration Audit

Prompt

We just migrated from WordPress to Next.js. Check that nothing is broken from an SEO perspective.

What the skill does

1. Compares old URL structure vs new — identifies 230 URLs that changed without 301 redirects 2. Checks canonical tags on new site — finds 45 pages with canonicals pointing to old WordPress URLs 3. Validates structured data survived migration — finds Product schema was lost on all product pages 4. Checks robots.txt — finds staging robots.txt was deployed to production (Disallow: /) 5. Produces critical migration fix list with priority order

Technical SEO Audit — Reference

HTTP Status Code Guide

robots.txt Syntax Reference

# Block a directory
User-agent: *
Disallow: /admin/
Disallow: /private/
Disallow: /search?   # Block search result pages

# Allow a specific file in a blocked directory
User-agent: *
Disallow: /images/
Allow: /images/logo.png

# Block specific crawlers
User-agent: AhrefsBot
Disallow: /

# Sitemap declaration
Sitemap: https://example.com/sitemap.xml

Canonical Tag Patterns

Correct Implementations

<!-- Self-referencing canonical (every page should have one) -->
<link rel="canonical" href="https://example.com/blog/article-title" />

<!-- Cross-domain canonical -->
<link rel="canonical" href="https://original.com/article" />

<!-- HTTP to HTTPS canonical -->
<link rel="canonical" href="https://example.com/page" />

Common Mistakes

Core Web Vitals Diagnostic Patterns

LCP Diagnosis

LCP > 2.5s
  └─ Is TTFB > 800ms?
      ├─ Yes → Server/hosting issue (CDN, caching, server capacity)
      └─ No → Client-side issue
           └─ Is LCP element an image?
               ├─ Yes → Check: format (WebP?), compression, dimensions, preload
               └─ No → Check: render-blocking CSS/JS, font loading

CLS Diagnosis

CLS > 0.1
  └─ Check above-the-fold content for:
      ├─ Images/videos without width/height attributes
      ├─ Ads/embeds injecting without reserved space
      ├─ Web fonts causing FOIT/FOUT
      ├─ Dynamic content injected after load (banners, popups)
      └─ CSS animations affecting layout (transform is safe; width/height are not)

Structured Data Quick Reference

Article Schema (Minimum)

{
  "@context": "https://schema.org",
  "@type": "Article",
  "headline": "Article Title",
  "author": {
    "@type": "Person",
    "name": "Author Name",
    "url": "https://example.com/author"
  },
  "datePublished": "2026-03-18",
  "dateModified": "2026-03-18",
  "publisher": {
    "@type": "Organization",
    "name": "Company Name",
    "logo": {
      "@type": "ImageObject",
      "url": "https://example.com/logo.png"
    }
  }
}

BreadcrumbList Schema

{
  "@context": "https://schema.org",
  "@type": "BreadcrumbList",
  "itemListElement": [
    {"@type": "ListItem", "position": 1, "name": "Home", "item": "https://example.com"},
    {"@type": "ListItem", "position": 2, "name": "Blog", "item": "https://example.com/blog"},
    {"@type": "ListItem", "position": 3, "name": "Article Title"}
  ]
}

Server Response Header Checklist

Crawl Budget Waste Indicators