ivangdavila_seo/technical.md

Technical SEO

Core Web Vitals

• LCP (Largest Contentful Paint): < 2.5s — largest visible element load time
• INP (Interaction to Next Paint): < 200ms — response to user interaction
• CLS (Cumulative Layout Shift): < 0.1 — visual stability, no jumping content
• Test with PageSpeed Insights — field data from real users matters more than lab
• Poor CWV = ranking demotion in competitive queries

Crawlability

• robots.txt: Disallow: /admin/ blocks crawlers — check with robots.txt Tester in GSC
• NEVER block CSS/JS in robots.txt — Google needs them to render JavaScript
• Crawl budget: large sites (>10K pages) must prioritize important pages
• Orphan pages (no internal links) won't get crawled regularly
• XML sitemap: max 50K URLs or 50MB per file, link in robots.txt

Indexing

• noindex meta tag: prevents indexing but wastes crawl budget
• canonical URL: self-referencing on all pages, cross-domain for syndicated content
• Parameter URLs (?sort=price) need canonical to main version
• Pagination: use rel="next"/"prev" or canonical to page 1, depending on content
• Check indexing in GSC: URL Inspection tool shows render and index status

Mobile

• Mobile-first indexing: Google indexes mobile version, desktop secondary
• Viewport meta tag required: <meta name="viewport" content="width=device-width, initial-scale=1">
• Touch targets minimum 48x48px — failing this hurts mobile usability score
• No intrusive interstitials — popups that block content get demoted
• Test with Mobile-Friendly Test — failing blocks ranking in mobile search

HTTPS

• Required for rankings — HTTP sites show "Not Secure" warning
• Mixed content (HTTP resources on HTTPS page) breaks padlock
• HSTS header: tells browsers to always use HTTPS
• After migration: 301 redirect all HTTP to HTTPS, update canonical URLs

Speed

• TTFB < 200ms — server response time, hosting matters
• Render-blocking CSS: inline critical CSS, defer rest
• JavaScript: async/defer attributes, avoid blocking main thread
• Images: lazy load, responsive srcset, modern formats (WebP/AVIF)
• Fonts: font-display: swap prevents invisible text during load
• CDN for static assets — reduces latency globally