SEO optimization
Search engine optimization based on Lighthouse SEO audits and Google Search guidelines. Focus on technical SEO, on-page optimization, and structured data.
SEO fundamentals
Search ranking factors (approximate influence):
| Factor | Influence | This Skill | |--------|-----------|------------| | Content quality & relevance | ~40% | Partial (structure) | | Backlinks & authority | ~25% | ✗ | | Technical SEO | ~15% | ✓ | | Page experience (Core Web Vitals) | ~10% | See [Core Web Vitals](../core-web-vitals/SKILL.md) | | On-page SEO | ~10% | ✓ |
Technical SEO
Crawlability
robots.txt:
# /robots.txt
User-agent: *
Allow: /
# Block admin/private areas
Disallow: /admin/
Disallow: /api/
Disallow: /private/
# Don't block resources needed for rendering
# ❌ Disallow: /static/
Sitemap: https://example.com/sitemap.xmlMeta robots:
<!-- Default: indexable, followable -->
<meta name="robots" content="index, follow">
<!-- Noindex specific pages -->
<meta name="robots" content="noindex, nofollow">
<!-- Indexable but don't follow links -->
<meta name="robots" content="index, nofollow">
<!-- Control snippets -->
<meta name="robots" content="max-snippet:150, max-image-preview:large">Canonical URLs:
<!-- Prevent duplicate content issues -->
<link rel="canonical" href="https://example.com/page">
<!-- Self-referencing canonical (recommended) -->
<link rel="canonical" href="https://example.com/current-page">
<!-- For paginated content -->
<link rel="canonical" href="https://example.com/products">
<!-- Or use rel="prev" / rel="next" for explicit pagination -->XML sitemap
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
<loc>https://example.com/</loc>
<lastmod>2024-01-15</lastmod>
<changefreq>daily</changefreq>
<priority>1.0</priority>
</url>
<url>
<loc>https://example.com/products</loc>
<lastmod>2024-01-14</lastmod>
<changefreq>weekly</changefreq>
<priority>0.8</priority>
</url>
</urlset>Sitemap best practices:
- Maximum 50,000 URLs or 50MB per sitemap
- Use sitemap index for larger sites
- Include only canonical, indexable URLs
- Update
lastmodwhen content changes - Submit to Google Search Console
URL structure
✅ Good URLs:
https://example.com/products/blue-widget
https://example.com/blog/how-to-use-widgets
❌ Poor URLs:
https://example.com/p?id=12345
https://example.com/products/item/category/subcategory/blue-widget-2024-sale-discountURL guidelines:
- Use hyphens, not underscores
- Lowercase only
- Keep short (< 75 characters)
- Include target keywords naturally
- Avoid parameters when possible
- Use HTTPS always
HTTPS & security
<!-- Ensure all resources use HTTPS -->
<img src="https://example.com/image.jpg">
<!-- Not: -->
<img src="http://example.com/image.jpg">Security headers for SEO trust signals:
Strict-Transport-Security: max-age=31536000; includeSubDomains
X-Content-Type-Options: nosniff
X-Frame-Options: DENYOn-page SEO
Title tags
<!-- ❌ Missing or generic -->
<title>Page</title>
<title>Home</title>
<!-- ✅ Descriptive with primary keyword -->
<title>Blue Widgets for Sale | Premium Quality | Example Store</title>Title tag guidelines:
- 50-60 characters (Google truncates ~60)
- Primary keyword near the beginning
- Unique for every page
- Brand name at end (unless homepage)
- Action-oriented when appropriate
Meta descriptions
<!-- ❌ Missing or duplicate -->
<meta name="description" content="">
<!-- ✅ Compelling and unique -->
<meta name="description" content="Shop premium blue widgets with free shipping. 30-day returns. Rated 4.9/5 by 10,000+ customers. Order today and save 20%.">Meta description guidelines:
- 150-160 characters
- Include primary keyword naturally
- Compelling call-to-action
- Unique for every page
- Matches page content
Heading structure
<!-- ❌ Poor structure -->
<h2>Welcome to Our Store</h2>
<h4>Products</h4>
<h1>Contact Us</h1>
<!-- ✅ Proper hierarchy -->
<h1>Blue Widgets - Premium Quality</h1>
<h2>Product Features</h2>
<h3>Durability</h3>
<h3>Design</h3>
<h2>Customer Reviews</h2>
<h2>Pricing</h2>Heading guidelines:
- Single
<h1>per page (the main topic) - Logical hierarchy (don't skip levels)
- Include keywords naturally
- Descriptive, not generic
Image SEO
<!-- ❌ Poor image SEO -->
<img src="IMG_12345.jpg">
<!-- ✅ Optimized image -->
<img src="blue-widget-product-photo.webp"
alt="Blue widget with chrome finish, side view showing control panel"
width="800"
height="600"
loading="lazy">Image guidelines:
- Descriptive filenames with keywords
- Alt text describes the image content
- Compressed and properly sized
- WebP/AVIF with fallbacks
- Lazy load below-fold images
Internal linking
<!-- ❌ Non-descriptive -->
<a href="/products">Click here</a>
<a href="/widgets">Read more</a>
<!-- ✅ Descriptive anchor text -->
<a href="/products/blue-widgets">Browse our blue widget collection</a>
<a href="/guides/widget-maintenance">Learn how to maintain your widgets</a>Linking guidelines:
- Descriptive anchor text with keywords
- Link to relevant internal pages
- Reasonable number of links per page
- Fix broken links promptly
- Use breadcrumbs for hierarchy
Structured data (JSON-LD)
Organization
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "Organization",
"name": "Example Company",
"url": "https://example.com",
"logo": "https://example.com/logo.png",
"sameAs": [
"https://twitter.com/example",
"https://linkedin.com/company/example"
],
"contactPoint": {
"@type": "ContactPoint",
"telephone": "+1-555-123-4567",
"contactType": "customer service"
}
}
</script>Article
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "Article",
"headline": "How to Choose the Right Widget",
"description": "Complete guide to selecting widgets for your needs.",
"image": "https://example.com/article-image.jpg",
"author": {
"@type": "Person",
"name": "Jane Smith",
"url": "https://example.com/authors/jane-smith"
},
"publisher": {
"@type": "Organization",
"name": "Example Blog",
"logo": {
"@type": "ImageObject",
"url": "https://example.com/logo.png"
}
},
"datePublished": "2024-01-15",
"dateModified": "2024-01-20"
}
</script>Product
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "Product",
"name": "Blue Widget Pro",
"image": "https://example.com/blue-widget.jpg",
"description": "Premium blue widget with advanced features.",
"brand": {
"@type": "Brand",
"name": "WidgetCo"
},
"offers": {
"@type": "Offer",
"price": "49.99",
"priceCurrency": "USD",
"availability": "https://schema.org/InStock",
"url": "https://example.com/products/blue-widget"
},
"aggregateRating": {
"@type": "AggregateRating",
"ratingValue": "4.8",
"reviewCount": "1250"
}
}
</script>FAQ
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "FAQPage",
"mainEntity": [
{
"@type": "Question",
"name": "What colors are available?",
"acceptedAnswer": {
"@type": "Answer",
"text": "Our widgets come in blue, red, and green."
}
},
{
"@type": "Question",
"name": "What is the warranty?",
"acceptedAnswer": {
"@type": "Answer",
"text": "All widgets include a 2-year warranty."
}
}
]
}
</script>Breadcrumbs
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "BreadcrumbList",
"itemListElement": [