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+# SEO Optimization
+
+**Technical SEO, content optimization, and search strategy**
+
+# Technical SEO Skill
+
+**Production-tested practices for technical SEO audits and implementation**
+
+This skill codifies technical SEO best practices from professional audits of high-performing websites.
+
+---
+
+## Core Principles
+
+1. **Crawlability First**: Search engines must find and access your content
+2. **Speed Matters**: Core Web Vitals directly impact rankings
+3. **Mobile-First**: Google indexes mobile version primarily
+4. **Structured Data**: Help search engines understand your content
+5. **User Experience**: Technical SEO serves human visitors
+
+---
+
+## The 10 Pillars of Technical SEO
+
+### 1. Site Architecture & Crawlability
+
+**Optimal Site Structure**:
+```
+Homepage (Level 0)
+├─ Category Pages (Level 1)
+│  ├─ Subcategory Pages (Level 2)
+│  │  └─ Individual Pages (Level 3)
+```
+
+**Best Practices**:
+- Maximum 3 clicks from homepage to any page
+- Logical URL hierarchy
+- Clear navigation structure
+- Internal linking strategy
+- XML sitemap for all important pages
+
+**robots.txt Configuration**:
+```txt
+# Allow all crawlers
+User-agent: *
+Allow: /
+
+# Block sensitive areas
+Disallow: /admin/
+Disallow: /api/
+Disallow: /private/
+Disallow: /*.pdf$
+
+# Block duplicate content
+Disallow: /*?sort=
+Disallow: /*?page=
+
+# Sitemap location
+Sitemap: https://example.com/sitemap.xml
+```
+
+**Common Mistakes**:
+- Blocking important pages in robots.txt
+- Orphaned pages (no internal links)
+- Infinite scroll without pagination
+- Deep page hierarchy (4+ levels)
+
+### 2. Core Web Vitals & Performance
+
+**The 3 Core Web Vitals**:
+
+**Largest Contentful Paint (LCP)** - Loading Performance
+- Target: < 2.5 seconds
+- Measures: When main content loads
+- Fix: Optimize images, reduce server response time, use CDN
+
+**First Input Delay (FID)** - Interactivity
+- Target: < 100 milliseconds
+- Measures: Time until page is interactive
+- Fix: Minimize JavaScript, code splitting, defer non-critical JS
+
+**Cumulative Layout Shift (CLS)** - Visual Stability
+- Target: < 0.1
+- Measures: Unexpected layout shifts
+- Fix: Set image dimensions, avoid inserting content above existing content
+
+**Performance Optimization Checklist**:
+- [ ] Images optimized (WebP/AVIF, compressed)
+- [ ] Lazy loading implemented
+- [ ] Critical CSS inlined
+- [ ] JavaScript deferred/async
+- [ ] CDN for static assets
+- [ ] Server response time < 200ms
+- [ ] Minified CSS/JS
+- [ ] Gzip/Brotli compression enabled
+
+### 3. Mobile-First Optimization
+
+**Mobile SEO Checklist**:
+- [ ] Responsive design (adapts to all screen sizes)
+- [ ] Viewport meta tag present
+- [ ] Touch targets ≥ 44x44px
+- [ ] Font size ≥ 16px for body text
+- [ ] No horizontal scrolling
+- [ ] Mobile page speed < 3 seconds
+- [ ] Tap targets well-spaced (48px spacing)
+- [ ] No mobile-specific errors in Search Console
+
+**Mobile-Friendly Meta Tag**:
+```html
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+```
+
+### 4. URL Structure & Management
+
+**SEO-Friendly URL Best Practices**:
+
+**Good URLs**:
+```
+✅ example.com/blog/seo-best-practices
+✅ example.com/products/running-shoes
+✅ example.com/services/web-design
+```
+
+**Bad URLs**:
+```
+❌ example.com/page.php?id=123&cat=5
+❌ example.com/Products_And_Services
+❌ example.com/p/12345
+```
+
+**URL Guidelines**:
+- Use hyphens, not underscores
+- Lowercase only
+- Include target keyword
+- Keep short (< 60 characters)
+- Logical hierarchy
+- No parameters if possible
+- Consistent trailing slash handling
+
+**Redirect Best Practices**:
+- Use 301 redirects for moved content
+- Avoid redirect chains (A→B→C)
+- Update internal links instead of redirecting
+- Redirect old URLs to most relevant new page
+
+### 5. HTML & Meta Tag Optimization
+
+**Essential Meta Tags**:
+
+```html
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <!-- Character encoding -->
+  <meta charset="UTF-8">
+
+  <!-- Viewport for mobile -->
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+
+  <!-- Title (50-60 characters) -->
+  <title>Page Title | Brand Name</title>
+
+  <!-- Meta description (150-160 characters) -->
+  <meta name="description" content="Compelling description with keywords">
+
+  <!-- Canonical URL -->
+  <link rel="canonical" href="https://example.com/page">
+
+  <!-- Open Graph for social -->
+  <meta property="og:title" content="Page Title">
+  <meta property="og:description" content="Description">
+  <meta property="og:image" content="https://example.com/og-image.jpg">
+  <meta property="og:url" content="https://example.com/page">
+  <meta property="og:type" content="website">
+
+  <!-- Twitter Card -->
+  <meta name="twitter:card" content="summary_large_image">
+  <meta name="twitter:title" content="Page Title">
+  <meta name="twitter:description" content="Description">
+  <meta name="twitter:image" content="https://example.com/twitter-image.jpg">
+
+  <!-- Robots meta (if needed) -->
+  <meta name="robots" content="index, follow">
+</head>
+```
+
+**Heading Hierarchy**:
+```html
+<h1>Single H1: Primary Page Topic</h1>
+
+<h2>Main Section 1</h2>
+<h3>Subsection 1.1</h3>
+<h3>Subsection 1.2</h3>
+
+<h2>Main Section 2</h2>
+<h3>Subsection 2.1</h3>
+
+<!-- Don't skip levels -->
+<!-- Don't use multiple H1s -->
+```
+
+### 6. Schema Markup (Structured Data)
+
+**Common Schema Types**:
+
+**Organization**:
+```json
+{
+  "@context": "https://schema.org",
+  "@type": "Organization",
+  "name": "Company Name",
+  "url": "https://example.com",
+  "logo": "https://example.com/logo.png",
+  "sameAs": [
+    "https://facebook.com/company",
+    "https://twitter.com/company",
+    "https://linkedin.com/company/company"
+  ]
+}
+```
+
+**Article**:
+```json
+{
+  "@context": "https://schema.org",
+  "@type": "Article",
+  "headline": "Article Title",
+  "image": "https://example.com/image.jpg",
+  "author": {
+    "@type": "Person",
+    "name": "Author Name"
+  },
+  "publisher": {
+    "@type": "Organization",
+    "name": "Publisher",
+    "logo": {
+      "@type": "ImageObject",
+      "url": "https://example.com/logo.png"
+    }
+  },
+  "datePublished": "2025-01-20",
+  "dateModified": "2025-01-20"
+}
+```
+
+**BreadcrumbList**:
+```json
+{
+  "@context": "https://schema.org",
+  "@type": "BreadcrumbList",
+  "itemListElement": [
+    {
+      "@type": "ListItem",
+      "position": 1,
+      "name": "Home",
+      "item": "https://example.com"
+    },
+    {
+      "@type": "ListItem",
+      "position": 2,
+      "name": "Category",
+      "item": "https://example.com/category"
+    }
+  ]
+}
+```
+
+### 7. Image SEO
+
+**Image Optimization Checklist**:
+- [ ] Descriptive file names (not IMG_1234.jpg)
+- [ ] Alt text on all images (except decorative)
+- [ ] Image dimensions specified (width/height)
+- [ ] Lazy loading for below-fold images
+- [ ] Modern formats (WebP, AVIF)
+- [ ] Compressed (TinyPNG, ImageOptim)
+- [ ] Responsive images (srcset)
+- [ ] Image sitemap (for image search)
+
+**Example**:
+```html
+<img
+  src="blue-running-shoes-800w.webp"
+  srcset="blue-running-shoes-400w.webp 400w,
+          blue-running-shoes-800w.webp 800w,
+          blue-running-shoes-1200w.webp 1200w"
+  sizes="(max-width: 600px) 400px,
+         (max-width: 1000px) 800px,
+         1200px"
+  alt="Blue Nike running shoes on white background"
+  width="800"
+  height="600"
+  loading="lazy"
+  decoding="async"
+/>
+```
+
+### 8. Security & HTTPS
+
+**Security Checklist**:
+- [ ] SSL certificate installed and valid
+- [ ] All pages served over HTTPS
+- [ ] HTTP redirects to HTTPS (301)
+- [ ] No mixed content (HTTP resources on HTTPS pages)
+- [ ] HSTS header implemented
+- [ ] Security headers configured
+
+**Essential Security Headers**:
+```
+Strict-Transport-Security: max-age=31536000; includeSubDomains
+X-Frame-Options: SAMEORIGIN
+X-Content-Type-Options: nosniff
+Referrer-Policy: strict-origin-when-cross-origin
+Permissions-Policy: geolocation=(), microphone=(), camera=()
+```
+
+### 9. International & Multi-Language SEO
+
+**Hreflang Implementation**:
+
+```html
+<!-- Current page (English US) -->
+<link rel="alternate" hreflang="en-us" href="https://example.com/en-us/page" />
+
+<!-- Other language versions -->
+<link rel="alternate" hreflang="en-gb" href="https://example.com/en-gb/page" />
+<link rel="alternate" hreflang="es-es" href="https://example.com/es-es/page" />
+<link rel="alternate" hreflang="fr-fr" href="https://example.com/fr-fr/page" />
+
+<!-- Default for language selector -->
+<link rel="alternate" hreflang="x-default" href="https://example.com/page" />
+```
+
+**Best Practices**:
+- Use correct language-region codes (en-US, not just en)
+- Include self-referential hreflang
+- Include x-default for unmatched regions
+- Same URL structure across languages
+- Translate meta tags and structured data
+
+### 10. Indexability & Search Console
+
+**Indexability Checklist**:
+- [ ] Important pages indexed (check: site:example.com)
+- [ ] No accidental noindex tags
+- [ ] Sitemap submitted to Search Console
+- [ ] Sitemap includes all important pages
+- [ ] No crawl errors in Search Console
+- [ ] Coverage report clean
+- [ ] Mobile usability issues resolved
+
+**XML Sitemap Best Practices**:
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+  <url>
+    <loc>https://example.com/page</loc>
+    <lastmod>2025-01-20</lastmod>
+    <changefreq>weekly</changefreq>
+    <priority>0.8</priority>
+  </url>
+</urlset>
+```
+
+- Include only canonical URLs
+- Update lastmod when content changes
+- Split large sitemaps (> 50,000 URLs)
+- Exclude noindex pages
+- Include images in sitemap or separate image sitemap
+
+---
+
+## Technical SEO Audit Framework
+
+### Phase 1: Discovery (30 minutes)
+
+**Identify**:
+- Site type and framework
+- Number of pages
+- Site structure
+- Key templates
+- Existing issues
+
+**Tools**:
+- Google Search Console
+- Screaming Frog (crawl)
+- PageSpeed Insights
+- Mobile-Friendly Test
+
+### Phase 2: Analysis (2-3 hours)
+
+**Audit all 10 pillars**:
+1. Site architecture
+2. Core Web Vitals
+3. Mobile optimization
+4. URL structure
+5. HTML/meta tags
+6. Schema markup
+7. Image SEO
+8. Security
+9. International (if applicable)
+10. Indexability
+
+**Document**:
+- Specific issues with file paths
+- Severity (Critical/High/Medium/Low)
+- Impact on SEO
+- Fix recommendations
+
+### Phase 3: Reporting (1 hour)
+
+**Report structure**:
+- Executive summary
+- Issue count by severity
+- Detailed findings by category
+- Priority action plan
+- Expected impact
+
+---
+
+## Common Technical SEO Issues
+
+### Critical Issues (Fix Immediately)
+
+1. **Site Not Indexed**
+   - Issue: noindex on all pages
+   - Impact: Site invisible to search engines
+   - Fix: Remove noindex tags
+
+2. **Robots.txt Blocking Site**
+   - Issue: Disallow: / in robots.txt
+   - Impact: Crawlers can't access site
+   - Fix: Update robots.txt
+
+3. **No HTTPS**
+   - Issue: Site on HTTP
+   - Impact: Security warning, ranking penalty
+   - Fix: Install SSL certificate
+
+4. **Severe Performance Issues**
+   - Issue: Page load > 10 seconds
+   - Impact: High bounce rate, ranking penalty
+   - Fix: Optimize images, code, server
+
+### High Priority (Fix This Week)
+
+1. **Missing Title Tags**
+   - Impact: Poor click-through rate
+   - Fix: Add unique title to every page
+
+2. **Missing Meta Descriptions**
+   - Impact: Less compelling search results
+   - Fix: Add compelling descriptions
+
+3. **Not Mobile-Friendly**
+   - Impact: Mobile ranking penalty
+   - Fix: Implement responsive design
+
+4. **Broken Internal Links**
+   - Impact: Poor UX, wasted crawl budget
+   - Fix: Update or remove broken links
+
+### Medium Priority (Fix This Month)
+
+1. **Suboptimal URL Structure**
+   - Impact: Missed keyword opportunity
+   - Fix: Implement clean URLs (with redirects)
+
+2. **Missing Schema Markup**
+   - Impact: Missed rich snippet opportunity
+   - Fix: Implement relevant schema types
+
+3. **Images Without Alt Text**
+   - Impact: Accessibility and image search
+   - Fix: Add descriptive alt text
+
+4. **Slow Page Speed (3-5s)**
+   - Impact: Moderate ranking factor
+   - Fix: Optimize performance
+
+---
+
+## Framework-Specific Considerations
+
+### Next.js SEO Optimization
+
+```typescript
+// app/layout.tsx
+export const metadata = {
+  metadataBase: new URL('https://example.com'),
+  title: {
+    default: 'Site Name',
+    template: '%s | Site Name'
+  },
+  description: 'Default description',
+  robots: {
+    index: true,
+    follow: true,
+  },
+}
+
+// app/page.tsx
+export const metadata = {
+  title: 'Page Title',
+  description: 'Page description',
+  openGraph: {
+    title: 'Page Title',
+    description: 'Page description',
+    images: ['/og-image.jpg'],
+  },
+}
+
+// Generate sitemap
+export default function sitemap() {
+  return [
+    {
+      url: 'https://example.com',
+      lastModified: new Date(),
+    },
+  ]
+}
+
+// robots.txt
+export default function robots() {
+  return {
+    rules: {
+      userAgent: '*',
+      allow: '/',
+      disallow: '/admin/',
+    },
+    sitemap: 'https://example.com/sitemap.xml',
+  }
+}
+```
+
+### WordPress SEO
+
+**Essential Plugins**:
+- Yoast SEO or Rank Math (on-page optimization)
+- WP Rocket or W3 Total Cache (performance)
+- Smush or ShortPixel (image optimization)
+- Redirection (301 redirects)
+
+**wp-config.php optimizations**:
+```php
+// Disable file editing
+define('DISALLOW_FILE_EDIT', true);
+
+// Enable caching
+define('WP_CACHE', true);
+
+// Increase memory limit
+define('WP_MEMORY_LIMIT', '256M');
+```
+
+### Static Site Generators (Gatsby, Hugo, Jekyll)
+
+**Advantages**:
+- Blazing fast (static HTML)
+- Inherently secure
+- Easy to cache
+
+**SEO Setup**:
+- Configure meta tags in templates
+- Generate sitemap at build time
+- Optimize images during build
+- Implement schema in templates
+- Configure redirects in netlify.toml or _redirects
+
+---
+
+## Testing & Validation
+
+### Essential Tools
+
+**Free Tools**:
+- Google Search Console (indexing, errors)
+- Google PageSpeed Insights (performance)
+- Google Mobile-Friendly Test
+- Google Rich Results Test (schema)
+- Lighthouse (comprehensive audit)
+- Screaming Frog (free up to 500 URLs)
+
+**Paid Tools**:
+- Screaming Frog (full site crawls)
+- Ahrefs Site Audit
+- SEMrush Site Audit
+- Sitebulb
+- OnCrawl
+
+### Validation Checklist
+
+After implementing fixes:
+- [ ] Run PageSpeed Insights (mobile & desktop)
+- [ ] Test with Mobile-Friendly Test
+- [ ] Validate schema with Rich Results Test
+- [ ] Check Search Console for errors
+- [ ] Crawl site with Screaming Frog
+- [ ] Verify redirects work correctly
+- [ ] Test all critical user flows
+- [ ] Check canonical tags point correctly
+
+---
+
+## Monitoring & Maintenance
+
+### Monthly Checks
+
+- [ ] Google Search Console errors
+- [ ] Core Web Vitals performance
+- [ ] New 404 errors
+- [ ] Security issues
+- [ ] Mobile usability issues
+- [ ] Indexing coverage
+
+### Quarterly Audits
+
+- [ ] Full site crawl
+- [ ] Backlink profile review
+- [ ] Content freshness audit
+- [ ] Technical SEO health check
+- [ ] Competitor analysis
+
+---
+
+## Success Metrics
+
+**Technical SEO KPIs**:
+- **Crawl Efficiency**: Pages crawled / Total pages
+- **Index Coverage**: Pages indexed / Total pages
+- **Core Web Vitals**: LCP, FID, CLS scores
+- **Mobile Usability**: Issues in Search Console
+- **Page Speed**: Load time improvement
+- **Error Rate**: 404s, 500s, crawl errors
+
+**Targets**:
+- 95%+ important pages indexed
+- Core Web Vitals: All "Good"
+- 0 critical errors in Search Console
+- < 1% 404 error rate
+- Mobile page speed < 3 seconds
+
+---
+
+**Version**: 1.0
+**Last Updated**: January 2025
+**Framework Coverage**: Next.js, WordPress, Static Sites
+**Compliance**: Google Search Essentials, Core Web Vitals