The Complete Technical SEO Checklist for 2026

Crawlability & Indexing

Robots.txt

• Ensure robots.txt is accessible at /robots.txt
• Don't block important resources (CSS, JS, images)
• Include sitemap reference
• Test with Google's robots.txt tester

XML Sitemaps

• Submit sitemap to Google Search Console
• Keep sitemaps under 50MB / 50,000 URLs
• Include only canonical URLs
• Update lastmod dates accurately

Canonicalization

• Implement self-referencing canonicals
• Handle www vs non-www consistently
• Manage trailing slashes uniformly
• Handle pagination with rel=canonical or rel=prev/next

Core Web Vitals

Largest Contentful Paint (LCP)

Target: Under 2.5 seconds. Optimize by:

• Preloading critical resources
• Optimizing images (WebP/AVIF, lazy loading)
• Using CDN for static assets
• Minimizing render-blocking resources

Interaction to Next Paint (INP)

Target: Under 200 milliseconds. Optimize by:

• Breaking up long JavaScript tasks
• Using web workers for heavy computation
• Debouncing event handlers
• Prioritizing visible content rendering

Cumulative Layout Shift (CLS)

Target: Under 0.1. Optimize by:

• Setting explicit dimensions for images/videos
• Reserving space for ads and embeds
• Avoiding inserting content above existing content
• Using transform animations instead of layout-triggering properties

Mobile Optimization

• Implement responsive design
• Use viewport meta tag correctly
• Ensure tap targets are appropriately sized (48x48px minimum)
• Avoid intrusive interstitials
• Test with mobile-friendly test tool

Security

• Use HTTPS across entire site
• Implement HSTS headers
• Avoid mixed content
• Keep CMS and plugins updated
• Implement CSP headers

Structured Data

• Implement relevant schema markup (Article, Product, FAQ, etc.)
• Validate with Rich Results Test
• Use JSON-LD format (preferred)
• Keep structured data accurate and updated