---
name: technical-seo-checker
description: Performs technical SEO audits covering site speed, crawlability, indexability, mobile-friendliness, security, and structured data. Identifies technical issues preventing optimal search performance.
---

# Technical SEO Checker

This skill performs comprehensive technical SEO audits to identify issues that may prevent search engines from properly crawling, indexing, and ranking your site.

## When to Use This Skill

- Launching a new website
- Diagnosing ranking drops
- Pre-migration SEO audits
- Regular technical health checks
- Identifying crawl and index issues
- Improving site performance
- Fixing Core Web Vitals issues

## What This Skill Does

1. **Crawlability Audit**: Checks robots.txt, sitemaps, crawl issues
2. **Indexability Review**: Analyzes index status and blockers
3. **Site Speed Analysis**: Evaluates Core Web Vitals and performance
4. **Mobile-Friendliness**: Checks mobile optimization
5. **Security Check**: Reviews HTTPS and security headers
6. **Structured Data Audit**: Validates schema markup
7. **URL Structure Analysis**: Reviews URL patterns and redirects
8. **International SEO**: Checks hreflang and localization

## How to Use

### Full Technical Audit

```
Perform a technical SEO audit for [URL/domain]
```

### Specific Issue Check

```
Check Core Web Vitals for [URL]
```

```
Audit crawlability and indexability for [domain]
```

### Pre-Migration Audit

```
Technical SEO checklist for migrating [old domain] to [new domain]
```

## Instructions

When a user requests a technical SEO audit:

1. **Audit Crawlability**

   ```markdown
   ## Crawlability Analysis
   
   ### Robots.txt Review
   
   **URL**: [domain]/robots.txt
   **Status**: [Found/Not Found/Error]
   
   **Current Content**:
   ```
   [robots.txt content]
   ```
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | File exists | ✅/❌ | [notes] |
   | Valid syntax | ✅/⚠️/❌ | [errors found] |
   | Sitemap declared | ✅/❌ | [sitemap URL] |
   | Important pages blocked | ✅/⚠️/❌ | [blocked paths] |
   | Assets blocked | ✅/⚠️/❌ | [CSS/JS blocked?] |
   | Correct user-agents | ✅/⚠️/❌ | [notes] |
   
   **Issues Found**:
   - [Issue 1]
   - [Issue 2]
   
   **Recommended robots.txt**:
   ```
   User-agent: *
   Allow: /
   Disallow: /admin/
   Disallow: /private/
   
   Sitemap: https://example.com/sitemap.xml
   ```
   
   ---
   
   ### XML Sitemap Review
   
   **Sitemap URL**: [URL]
   **Status**: [Found/Not Found/Error]
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | Sitemap exists | ✅/❌ | [notes] |
   | Valid XML format | ✅/⚠️/❌ | [errors] |
   | In robots.txt | ✅/❌ | [notes] |
   | Submitted to GSC | ✅/⚠️/❌ | [notes] |
   | URLs count | [X] | [appropriate?] |
   | Only indexable URLs | ✅/⚠️/❌ | [notes] |
   | Includes priority | ✅/⚠️ | [notes] |
   | Includes lastmod | ✅/⚠️ | [accurate?] |
   
   **Issues Found**:
   - [Issue 1]
   
   ---
   
   ### Crawl Budget Analysis
   
   | Factor | Status | Impact |
   |--------|--------|--------|
   | Crawl errors | [X] errors | [Low/Med/High] |
   | Duplicate content | [X] pages | [Low/Med/High] |
   | Thin content | [X] pages | [Low/Med/High] |
   | Redirect chains | [X] found | [Low/Med/High] |
   | Orphan pages | [X] found | [Low/Med/High] |
   
   **Crawlability Score**: [X]/10
   ```

2. **Audit Indexability**

   ```markdown
   ## Indexability Analysis
   
   ### Index Status Overview
   
   | Metric | Count | Notes |
   |--------|-------|-------|
   | Pages in sitemap | [X] | |
   | Pages indexed | [X] | [source: site: search] |
   | Index coverage ratio | [X]% | [good if >90%] |
   
   ### Index Blockers Check
   
   | Blocker Type | Found | Pages Affected |
   |--------------|-------|----------------|
   | noindex meta tag | [X] | [list or "none"] |
   | noindex X-Robots | [X] | [list or "none"] |
   | Robots.txt blocked | [X] | [list or "none"] |
   | Canonical to other | [X] | [list or "none"] |
   | 4xx/5xx errors | [X] | [list or "none"] |
   | Redirect loops | [X] | [list or "none"] |
   
   ### Canonical Tags Audit
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | Canonicals present | ✅/⚠️/❌ | [X]% of pages |
   | Self-referencing | ✅/⚠️/❌ | [notes] |
   | Consistent (HTTP/HTTPS) | ✅/⚠️/❌ | [notes] |
   | Consistent (www/non-www) | ✅/⚠️/❌ | [notes] |
   | No conflicting signals | ✅/⚠️/❌ | [notes] |
   
   ### Duplicate Content Issues
   
   | Issue Type | Count | Examples |
   |------------|-------|----------|
   | Exact duplicates | [X] | [URLs] |
   | Near duplicates | [X] | [URLs] |
   | Parameter duplicates | [X] | [URLs] |
   | WWW/non-WWW | [X] | [notes] |
   | HTTP/HTTPS | [X] | [notes] |
   
   **Indexability Score**: [X]/10
   ```

3. **Audit Site Speed & Core Web Vitals**

   ```markdown
   ## Performance Analysis
   
   ### Core Web Vitals
   
   | Metric | Mobile | Desktop | Target | Status |
   |--------|--------|---------|--------|--------|
   | LCP (Largest Contentful Paint) | [X]s | [X]s | <2.5s | ✅/⚠️/❌ |
   | FID (First Input Delay) | [X]ms | [X]ms | <100ms | ✅/⚠️/❌ |
   | CLS (Cumulative Layout Shift) | [X] | [X] | <0.1 | ✅/⚠️/❌ |
   | INP (Interaction to Next Paint) | [X]ms | [X]ms | <200ms | ✅/⚠️/❌ |
   
   ### Additional Performance Metrics
   
   | Metric | Value | Status |
   |--------|-------|--------|
   | Time to First Byte (TTFB) | [X]ms | ✅/⚠️/❌ |
   | First Contentful Paint (FCP) | [X]s | ✅/⚠️/❌ |
   | Speed Index | [X] | ✅/⚠️/❌ |
   | Total Blocking Time | [X]ms | ✅/⚠️/❌ |
   | Page Size | [X]MB | ✅/⚠️/❌ |
   | Requests | [X] | ✅/⚠️/❌ |
   
   ### Performance Issues
   
   **LCP Issues**:
   - [Issue]: [Impact] - [Solution]
   - [Issue]: [Impact] - [Solution]
   
   **CLS Issues**:
   - [Issue]: [Impact] - [Solution]
   
   **Resource Loading**:
   | Resource Type | Count | Size | Issues |
   |---------------|-------|------|--------|
   | Images | [X] | [X]MB | [notes] |
   | JavaScript | [X] | [X]MB | [notes] |
   | CSS | [X] | [X]KB | [notes] |
   | Fonts | [X] | [X]KB | [notes] |
   
   ### Optimization Recommendations
   
   **High Impact**:
   1. [Recommendation] - Est. improvement: [X]s
   2. [Recommendation] - Est. improvement: [X]s
   
   **Medium Impact**:
   1. [Recommendation]
   2. [Recommendation]
   
   **Performance Score**: [X]/10
   ```

4. **Audit Mobile-Friendliness**

   ```markdown
   ## Mobile Optimization Analysis
   
   ### Mobile-Friendly Test
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | Mobile-friendly overall | ✅/❌ | [notes] |
   | Viewport configured | ✅/❌ | [viewport tag] |
   | Text readable | ✅/⚠️/❌ | Font size: [X]px |
   | Tap targets sized | ✅/⚠️/❌ | [notes] |
   | Content fits viewport | ✅/❌ | [notes] |
   | No horizontal scroll | ✅/❌ | [notes] |
   
   ### Responsive Design Check
   
   | Element | Desktop | Mobile | Issues |
   |---------|---------|--------|--------|
   | Navigation | [status] | [status] | [notes] |
   | Images | [status] | [status] | [notes] |
   | Forms | [status] | [status] | [notes] |
   | Tables | [status] | [status] | [notes] |
   | Videos | [status] | [status] | [notes] |
   
   ### Mobile-First Indexing
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | Mobile version has all content | ✅/⚠️/❌ | [notes] |
   | Mobile has same structured data | ✅/⚠️/❌ | [notes] |
   | Mobile has same meta tags | ✅/⚠️/❌ | [notes] |
   | Mobile images have alt text | ✅/⚠️/❌ | [notes] |
   
   **Mobile Score**: [X]/10
   ```

5. **Audit Security & HTTPS**

   ```markdown
   ## Security Analysis
   
   ### HTTPS Status
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | SSL certificate valid | ✅/❌ | Expires: [date] |
   | HTTPS enforced | ✅/❌ | [redirects properly?] |
   | Mixed content | ✅/⚠️/❌ | [X] issues |
   | HSTS enabled | ✅/⚠️ | [notes] |
   | Certificate chain | ✅/⚠️/❌ | [notes] |
   
   ### Security Headers
   
   | Header | Present | Value | Recommended |
   |--------|---------|-------|-------------|
   | Content-Security-Policy | ✅/❌ | [value] | [recommendation] |
   | X-Frame-Options | ✅/❌ | [value] | DENY or SAMEORIGIN |
   | X-Content-Type-Options | ✅/❌ | [value] | nosniff |
   | X-XSS-Protection | ✅/❌ | [value] | 1; mode=block |
   | Referrer-Policy | ✅/❌ | [value] | [recommendation] |
   
   **Security Score**: [X]/10
   ```

6. **Audit URL Structure**

   ```markdown
   ## URL Structure Analysis
   
   ### URL Pattern Review
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | HTTPS URLs | ✅/⚠️/❌ | [X]% HTTPS |
   | Lowercase URLs | ✅/⚠️/❌ | [notes] |
   | No special characters | ✅/⚠️/❌ | [notes] |
   | Readable/descriptive | ✅/⚠️/❌ | [notes] |
   | Appropriate length | ✅/⚠️/❌ | Avg: [X] chars |
   | Keywords in URLs | ✅/⚠️/❌ | [notes] |
   | Consistent structure | ✅/⚠️/❌ | [notes] |
   
   ### URL Issues Found
   
   | Issue Type | Count | Examples |
   |------------|-------|----------|
   | Dynamic parameters | [X] | [URLs] |
   | Session IDs in URLs | [X] | [URLs] |
   | Uppercase characters | [X] | [URLs] |
   | Special characters | [X] | [URLs] |
   | Very long URLs (>100) | [X] | [URLs] |
   
   ### Redirect Analysis
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | Redirect chains | [X] found | [max chain length] |
   | Redirect loops | [X] found | [URLs] |
   | 302 → 301 needed | [X] found | [URLs] |
   | Broken redirects | [X] found | [URLs] |
   
   **URL Score**: [X]/10
   ```

7. **Audit Structured Data**

   ```markdown
   ## Structured Data Analysis
   
   ### Schema Markup Found
   
   | Schema Type | Pages | Valid | Errors |
   |-------------|-------|-------|--------|
   | [Type 1] | [X] | ✅/❌ | [errors] |
   | [Type 2] | [X] | ✅/❌ | [errors] |
   
   ### Validation Results
   
   **Errors**:
   - [Error 1]: [affected pages] - [solution]
   - [Error 2]: [affected pages] - [solution]
   
   **Warnings**:
   - [Warning 1]: [notes]
   
   ### Missing Schema Opportunities
   
   | Page Type | Current Schema | Recommended |
   |-----------|----------------|-------------|
   | Blog posts | [current] | Article + FAQ |
   | Products | [current] | Product + Review |
   | Homepage | [current] | Organization |
   
   **Structured Data Score**: [X]/10
   ```

8. **Audit International SEO (if applicable)**

   ```markdown
   ## International SEO Analysis
   
   ### Hreflang Implementation
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | Hreflang tags present | ✅/❌ | [notes] |
   | Self-referencing | ✅/⚠️/❌ | [notes] |
   | Return tags present | ✅/⚠️/❌ | [notes] |
   | Valid language codes | ✅/⚠️/❌ | [notes] |
   | x-default tag | ✅/⚠️ | [notes] |
   
   ### Language/Region Targeting
   
   | Language | URL | Hreflang | Status |
   |----------|-----|----------|--------|
   | [en-US] | [URL] | [tag] | ✅/⚠️/❌ |
   | [es-ES] | [URL] | [tag] | ✅/⚠️/❌ |
   
   **International Score**: [X]/10
   ```

9. **Generate Technical Audit Summary**

   ```markdown
   # Technical SEO Audit Report
   
   **Domain**: [domain]
   **Audit Date**: [date]
   **Pages Analyzed**: [X]
   
   ## Overall Technical Health: [X]/100
   
   ```
   Score Breakdown:
   ████████░░ Crawlability: 8/10
   ███████░░░ Indexability: 7/10
   █████░░░░░ Performance: 5/10
   ████████░░ Mobile: 8/10
   █████████░ Security: 9/10
   ██████░░░░ URL Structure: 6/10
   █████░░░░░ Structured Data: 5/10
   ```
   
   ## Critical Issues (Fix Immediately)
   
   1. **[Issue]**: [Impact] 
      - Affected: [pages/scope]
      - Solution: [specific fix]
      - Priority: 🔴 Critical
   
   2. **[Issue]**: [Impact]
      - Affected: [pages/scope]
      - Solution: [specific fix]
      - Priority: 🔴 Critical
   
   ## High Priority Issues
   
   1. **[Issue]**: [Solution]
   2. **[Issue]**: [Solution]
   
   ## Medium Priority Issues
   
   1. **[Issue]**: [Solution]
   2. **[Issue]**: [Solution]
   
   ## Quick Wins
   
   These can be fixed quickly for immediate improvement:
   
   1. [Quick fix 1]
   2. [Quick fix 2]
   3. [Quick fix 3]
   
   ## Implementation Roadmap
   
   ### Week 1: Critical Fixes
   - [ ] [Task 1]
   - [ ] [Task 2]
   
   ### Week 2-3: High Priority
   - [ ] [Task 1]
   - [ ] [Task 2]
   
   ### Week 4+: Optimization
   - [ ] [Task 1]
   - [ ] [Task 2]
   
   ## Monitoring Recommendations
   
   Set up alerts for:
   - Core Web Vitals drops
   - Crawl error spikes
   - Index coverage changes
   - Security issues
   ```

## Example

**User**: "Check the technical SEO of example.com"

**Output**: [Comprehensive technical audit following the structure above]

## Technical SEO Checklist

```markdown
### Crawlability
- [ ] robots.txt is valid and not blocking important content
- [ ] XML sitemap exists and is submitted to GSC
- [ ] No crawl errors in Search Console
- [ ] No redirect chains or loops

### Indexability  
- [ ] Important pages are indexable
- [ ] Canonical tags are correct
- [ ] No duplicate content issues
- [ ] Pagination is handled correctly

### Performance
- [ ] Core Web Vitals pass
- [ ] Page speed under 3 seconds
- [ ] Images are optimized
- [ ] JS/CSS are minified

### Mobile
- [ ] Mobile-friendly test passes
- [ ] Viewport is configured
- [ ] Touch elements are properly sized

### Security
- [ ] HTTPS is enforced
- [ ] SSL certificate is valid
- [ ] No mixed content
- [ ] Security headers present

### Structure
- [ ] URLs are clean and descriptive
- [ ] Site architecture is logical
- [ ] Internal linking is strong
```

## Tips for Success

1. **Prioritize by impact** - Fix critical issues first
2. **Monitor continuously** - Use Search Console alerts
3. **Test changes** - Verify fixes work before deploying widely
4. **Document everything** - Track changes for troubleshooting
5. **Regular audits** - Schedule quarterly technical reviews

## Related Skills

- [on-page-seo-auditor](../on-page-seo-auditor/) - On-page SEO audit
- [schema-markup-generator](../../build/schema-markup-generator/) - Fix schema issues
- [performance-reporter](../../monitor/performance-reporter/) - Monitor improvements
- [internal-linking-optimizer](../internal-linking-optimizer/) - Fix link issues