Phase 9 - Performance & SEO

Overview

• Tier: Polish (Phase 9 of 12)
• Duration: 1-2 days
• Dependencies: Phase 0-8 completed
• Deliverables: Optimized site, performance reports, SEO implementation, monitoring setup

Entry Criteria

• QA testing complete
• All bugs fixed
• Content finalized
• Images already optimized (Phase 7)

Implementation Steps

Step	Task	Scope	Notes
9.01	Audit current performance	Essential	Baseline metrics
9.02	Optimize critical path	Essential	CSS, fonts, scripts
9.03	Implement caching strategy	Essential	Headers, service worker
9.04	Minify and compress	Essential	HTML, CSS, JS
9.05	Set up CDN	Essential	Static assets
9.06	Optimize web fonts	Essential	Subset, preload
9.07	Technical SEO audit	Essential	Crawlability, indexing
9.08	Schema markup	Essential	Structured data
9.09	Generate sitemap	Essential	XML sitemap
9.10	Submit to search engines	Essential	Google, Bing
9.11	Performance monitoring	Advanced	RUM setup
9.12	Create performance budget CI	Recommended	Automated checks

Common Pitfalls

1. Ignoring Third-Party Scripts: External scripts killing performance

   • Solution: Lazy load, use facades, or self-host

2. Unoptimized Fonts: Loading entire font families

   • Solution: Subset fonts, use variable fonts, preload critical

3. Missing Caching Headers: Not leveraging browser cache

   • Solution: Set appropriate cache-control headers

4. Blocking Resources: CSS/JS blocking render

   • Solution: Inline critical CSS, defer non-critical JS

5. Poor Image Strategy: Wrong formats or sizes

   • Solution: Use modern formats, responsive images

Exit Criteria

• Lighthouse scores meet targets (97+ performance)
• Core Web Vitals pass (LCP < 2.5s, INP ≤ 200ms, CLS < 0.1)
• All images optimized with modern formats
• Critical CSS inlined, non-critical deferred
• Fonts subsetted and preloaded
• Caching strategy implemented
• Service worker active (Advanced)
• SEO audit passes
• Schema markup implemented
• Sitemap generated and submitted
• Performance monitoring active (Advanced)
• Bundle sizes within budget

Rollback Strategy

If performance degrades:

1. Script Issues:

   • Remove problematic third-party scripts
   • Revert to previous bundle configuration
   • Check for unintended dependencies

2. Style Regression:

   • Verify critical CSS extraction
   • Check for CSS-in-JS issues
   • Revert style changes

3. Image Problems:

   • Re-run optimization pipeline
   • Check CDN configuration
   • Verify responsive images

AI Assistant Notes

Key Files to Reference

• astro.config.mjs - Build optimizations
• public/_headers - Caching strategy
• Performance audit scripts
• Lighthouse configuration

Common Prompts for This Phase

• “Optimize bundle size for production”
• “Implement Core Web Vitals monitoring”
• “Set up caching headers for static assets”
• “Create performance budget CI workflow”

Context Requirements

• Current performance metrics
• Target audience geography
• CDN preferences
• Analytics platform