v1.0 to v1.0

---

name: seo

description: Optimize for search engine visibility and ranking. Use when asked to "improve SEO", "optimize for search", "fix meta tags", "add structured data", "sitemap optimization", or "search engine optimization".

license: MIT

metadata:

author: web-quality-skills

---

# 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):

---

## Technical SEO

### Crawlability

**robots.txt:**

```text

# /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.xml

```

**Meta robots:**

```html

<!-- Default: indexable, followable -->

<!-- Noindex specific pages -->

<!-- Indexable but don't follow links -->

<!-- Control snippets -->

```

**Canonical URLs:**

```html

<!-- Prevent duplicate content issues -->

<!-- Self-referencing canonical (recommended) -->

<!-- For paginated content -->

<!-- Or use rel="prev" / rel="next" for explicit pagination -->

```

### XML sitemap

```xml

<?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 `lastmod` when 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-discount

```

**URL guidelines:**

- Use hyphens, not underscores

- Lowercase only

- Keep short (< 75 characters)

- Include target keywords naturally

- Avoid parameters when possible

- Use HTTPS always

### HTTPS & security

```html

<!-- Ensure all resources use HTTPS -->

<!-- Not: -->

```

**Security headers for SEO trust signals:**

```

Strict-Transport-Security: max-age=31536000; includeSubDomains

X-Content-Type-Options: nosniff

X-Frame-Options: DENY

```

---

## On-page SEO

### Title tags

```html

<!-- ❌ 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

```html

<!-- ❌ Missing or duplicate -->

<!-- ✅ Compelling and unique -->

```

**Meta description guidelines:**

- 150-160 characters

- Include primary keyword naturally

- Compelling call-to-action

- Unique for every page

- Matches page content

### Heading structure

```html

<!-- ❌ Poor structure -->

<h2>Welcome to Our Store</h2>

<h4>Products</h4>

<h1>Contact Us</h1>

<!-- ✅ Proper hierarchy -->

<h1>Blue Widgets - Premium Quality</h1>

```

**Heading guidelines:**

- Single `<h1>` per page (the main topic)

- Logical hierarchy (don't skip levels)

- Include keywords naturally

- Descriptive, not generic

### Image SEO

```html

<!-- ❌ Poor image SEO -->

<!-- ✅ Optimized image -->

```

**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

```html

<!-- ❌ 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

```html

<script type="application/ld+json">

}

</script>

```

### Article

```html

<script type="application/ld+json">

</script>

```

### Product

```html

<script type="application/ld+json">

}

</script>

```

### FAQ

```html

<script type="application/ld+json">

}

</script>

```

### Breadcrumbs

```html

<script type="application/ld+json">

</script>

```

### Validation

Test structured data at:

- [Google Rich Results Test](https://search.google.com/test/rich-results)

- [Schema.org Validator](https://validator.schema.org/)

---

## Mobile SEO

### Responsive design

```html

<!-- ❌ Not mobile-friendly -->

<!-- ✅ Responsive viewport -->

```

### Tap targets

```css

/* ❌ Too small for mobile */

.small-link {

padding: 4px;

font-size: 12px;

}

/* ✅ Adequate tap target */

.mobile-friendly-link {

padding: 12px;

font-size: 16px;

min-height: 48px;

min-width: 48px;

}

```

### Font sizes

```css

/* ❌ Too small on mobile */

body {

font-size: 10px;

}

/* ✅ Readable without zooming */

body {

font-size: 16px;

line-height: 1.5;

}

```

---

## International SEO

### Hreflang tags

```html

<!-- For multi-language sites -->

```

### Language declaration

```html

<html lang="en">

```

---

## SEO audit checklist

### Critical

- [ ] HTTPS enabled

- [ ] robots.txt allows crawling

- [ ] No `noindex` on important pages

- [ ] Title tags present and unique

- [ ] Single `<h1>` per page

### High priority

- [ ] Meta descriptions present

- [ ] Sitemap submitted

- [ ] Canonical URLs set

- [ ] Mobile-responsive

- [ ] Core Web Vitals passing

### Medium priority

- [ ] Structured data implemented

- [ ] Internal linking strategy

- [ ] Image alt text

- [ ] Descriptive URLs

- [ ] Breadcrumb navigation

### Ongoing

- [ ] Fix crawl errors in Search Console

- [ ] Update sitemap when content changes

- [ ] Monitor ranking changes

- [ ] Check for broken links

- [ ] Review Search Console insights

---

## Tools

| Google PageSpeed Insights | Performance + Core Web Vitals |

## References

- [Google Search Central](https://developers.google.com/search)

- [Schema.org](https://schema.org/)

- [Core Web Vitals](../core-web-vitals/SKILL.md)

- [Web Quality Audit](../web-quality-audit/SKILL.md)