Technical SEO Checklist: 25 Must-Do Fixes

Technical SEO ensures that search engines can efficiently find, crawl, render, and index your website. While content and links get most of the attention, technical issues can quietly prevent your best pages from ranking — no matter how good the content is.

Work through this checklist methodically. Even fixing a handful of these can produce noticeable improvements.

Crawling & Indexing

• 1. Check your robots.txt — Ensure you're not accidentally blocking important pages from being crawled. Visit yourdomain.com/robots.txt to inspect it.
• 2. Submit an XML sitemap — Create a sitemap and submit it in Google Search Console. Include only canonical, indexable URLs.
• 3. Fix crawl errors — Check the "Pages" report in Google Search Console for crawl errors and fix them promptly.
• 4. Ensure proper canonicalization — Use canonical tags to indicate the preferred version of duplicate or similar pages.
• 5. Audit noindex tags — Make sure important pages don't have noindex set unintentionally.

Site Speed & Core Web Vitals

• 6. Measure Core Web Vitals — Use Google PageSpeed Insights or Search Console's Core Web Vitals report to identify failing pages.
• 7. Enable compression — Gzip or Brotli compression reduces file sizes significantly. Verify it's enabled on your server.
• 8. Leverage browser caching — Set appropriate cache-control headers so returning visitors load pages faster.
• 9. Minify CSS, JS, and HTML — Remove unnecessary whitespace and comments from code files to reduce their size.
• 10. Optimise and compress images — Use WebP format and compress images with tools like Squoosh or Cloudinary.
• 11. Implement lazy loading — Load images and videos only when they enter the user's viewport.
• 12. Use a CDN — A content delivery network serves assets from servers closer to the user, reducing latency.

HTTPS & Security

• 13. Migrate to HTTPS — HTTPS is a confirmed (albeit minor) ranking signal. Every site should be on HTTPS in 2025.
• 14. Fix mixed content warnings — After moving to HTTPS, ensure all page resources (images, scripts) load over HTTPS, not HTTP.
• 15. Redirect HTTP to HTTPS — Set up server-level 301 redirects from all HTTP URLs to their HTTPS equivalents.

URL & Redirect Management

• 16. Fix broken links (404s) — Identify and fix or redirect broken internal and external links. These create poor user experiences and waste crawl budget.
• 17. Fix redirect chains — All redirects should go directly to the final destination URL. Chains (A → B → C) slow crawling and dilute authority.
• 18. Standardise your preferred domain — Decide on www vs. non-www and redirect all variations to your canonical preference.
• 19. Fix duplicate content — Identical or very similar content on multiple URLs confuses Google. Use canonical tags or 301 redirects to consolidate.

Mobile & UX

• 20. Verify mobile-friendliness — Google uses mobile-first indexing. Test your site with Google's Mobile-Friendly Test tool.
• 21. Fix intrusive interstitials — Pop-ups that obstruct content on mobile can trigger a Google penalty. Ensure they're not blocking the main content on load.
• 22. Check font sizes and tap targets — Text should be readable without zooming, and buttons/links should be large enough to tap easily on mobile.

Structured Data

• 23. Implement structured data (Schema.org) — Add appropriate schema markup (Article, FAQ, HowTo, Review, BreadcrumbList) to help Google understand your content and earn rich results.
• 24. Validate your structured data — Use Google's Rich Results Test to check for errors in your schema markup.
• 25. Add BreadcrumbList schema — Breadcrumb rich results can appear in SERPs and improve click-through rates.

Key Takeaways

• Technical SEO creates the foundation that allows all other SEO efforts to work.
• Start with crawl errors and indexing issues — they have the most direct impact.
• Core Web Vitals are now a ranking signal — speed and stability matter.
• Use automated audit tools regularly to catch regressions before they hurt rankings.