The Complete Technical SEO Checklist: Every Check That Matters in 2025

Crawlability Checks

Crawlability problems prevent search engines from accessing your content — the most fundamental category of technical issue.

1. Robots.txt is valid and correctly configured

• Access at yourdomain.com/robots.txt
• Verify it does not accidentally block Googlebot (User-agent: Googlebot with Disallow: /)
• Confirm your sitemap URL is referenced with a Sitemap: directive
• Use Google Search Console's robots.txt Tester tool to validate syntax

2. No important pages are blocked by robots.txt

• Review all Disallow rules against your actual URL structure
• Ensure your CSS and JavaScript files are NOT blocked (blocking them prevents proper rendering)
• Confirm tag, author, and archive disallow rules are intentional

3. Site is accessible over HTTPS with a valid certificate

• Check that SSL certificate is valid and not expired
• Verify https:// version loads correctly and http:// redirects to https://
• Test with Qualys SSL Labs for certificate configuration issues

4. No redirect chains or loops

• A redirects to B redirects to C is a chain — consolidate to A → C directly
• A redirects to B redirects to A is a loop — causing browsers to stop with an error
• Use a redirect checker or crawl tool to detect chains across your site

5. Server returns correct HTTP status codes

• Existing pages: 200
• Moved pages: 301 (permanent) or 302 (temporary)
• Deleted pages: 404 or 410 (gone)
• Avoid soft 404s — pages that return 200 but display "page not found" content

Indexing Checks

Indexing problems prevent your crawled pages from appearing in search results.

6. Important pages are not marked noindex

• Check Google Search Console > Coverage report for pages marked noindex
• Verify no CMS "discourage search engines" setting is accidentally enabled
• Inspect your template files for accidental noindex meta tags in conditional logic

7. Canonical tags are present and correct on all pages

• Every page should have a self-referencing canonical or canonical pointing to the preferred version
• Check for canonical conflicts: different canonical tag, og:url, and HTTP header sending different signals
• Paginated pages should use pagination signals (rel="next", rel="prev") rather than all pointing canonical at page 1

8. Duplicate content is resolved

• www vs non-www: one should 301 redirect to the other
• HTTP vs HTTPS: HTTP should 301 redirect to HTTPS
• Trailing slash vs no trailing slash: pick one and use canonicals consistently
• Query parameter duplicates: use canonical tags or Google Search Console parameter handling

9. XML sitemap contains only indexable pages

• Remove pages from sitemap that have noindex tags
• Remove redirects, 404 pages, and blocked pages from the sitemap
• Verify sitemap is submitted in Google Search Console and shows no errors

10. Google Search Console coverage report shows minimal errors

• Investigate and resolve Crawled - not indexed, Discovered - not indexed, and Excluded pages
• Prioritize fixing issues on your highest-value pages first

Page Speed and Core Web Vitals

Core Web Vitals are Google's user experience metrics that are confirmed ranking factors. Three metrics are measured: LCP, INP, and CLS.

11. Largest Contentful Paint (LCP) under 2.5 seconds

LCP measures how long the largest visible element (usually an image or heading) takes to render. Targets: Good < 2.5s, Needs Improvement 2.5–4s, Poor > 4s. Key optimizations: preload the LCP image, use a CDN, optimize image formats (WebP, AVIF), reduce server response time.

12. Interaction to Next Paint (INP) under 200ms

INP replaced FID and measures responsiveness to user interactions. Targets: Good < 200ms, Needs Improvement 200–500ms, Poor > 500ms. Key optimizations: reduce JavaScript execution time, defer non-critical JS, optimize event handlers.

13. Cumulative Layout Shift (CLS) under 0.1

CLS measures visual stability — how much page elements shift as the page loads. Targets: Good < 0.1, Needs Improvement 0.1–0.25, Poor > 0.25. Key optimizations: set explicit width/height on images and embeds, avoid injecting content above existing content.

14. Time to First Byte (TTFB) under 800ms

TTFB is the time from request to first byte of server response. Optimize server-side rendering, use edge caching, upgrade hosting, and implement CDN for static assets.

15. Mobile page speed checked separately from desktop

Google uses mobile-first indexing — performance on mobile is what counts for rankings. Test mobile performance specifically in Google PageSpeed Insights and prioritize mobile optimizations.

On-Page Technical Signals

On-page technical elements communicate content structure and meaning to crawlers.

16. Every page has a unique, optimized title tag

• Unique across the entire site
• Contains primary keyword, preferably near the front
• Under 60 characters (approximately 600 pixel width)

17. Every page has a unique meta description

• Unique across the entire site
• 120–155 characters
• Contains primary and secondary keywords naturally

18. H1 tag is present, unique, and contains the target keyword

• Exactly one H1 per page
• H1 closely matches or mirrors the title tag
• Subsequent headings (H2, H3) form a logical hierarchy

19. Internal linking structure connects all important pages

• All important pages reachable within 3 clicks from the homepage
• No orphan pages (pages with no internal links pointing to them)
• Anchor text is descriptive and keyword-relevant

20. Image alt text is present on all meaningful images

• Alt text describes the image content
• Primary keyword appears naturally in at least one image alt text per page
• Decorative images use empty alt text (alt="") to be ignored by screen readers and crawlers

21. URL structure is clean and descriptive

• URLs use hyphens to separate words, not underscores
• URLs contain the primary keyword where possible
• No session IDs, tracking parameters, or unnecessary query strings in canonical URLs

Structured Data and Schema Markup

Structured data helps search engines understand content type and enables rich results.

22. Schema markup is implemented on all relevant page types

• Article or BlogPosting on all editorial content
• Product + AggregateRating on all product pages
• FAQPage on all pages with Q&A sections
• LocalBusiness on business location pages
• BreadcrumbList on all content pages

23. All schema markup is validated with Google's Rich Results Test

• No required property errors
• Schema types match actual page content
• Markup is visible on the page (not hidden)

24. Open Graph and Twitter Card tags on all pages

• og:title, og:description, og:image, og:url, og:type on every page
• twitter:card type set appropriately
• og:image is at least 1200×630 px and served over HTTPS

25. Breadcrumb navigation matches BreadcrumbList schema

• Visible breadcrumb navigation on page
• Schema breadcrumbs match the visible breadcrumb paths exactly

Mobile and International SEO Checks

Google uses mobile-first indexing — the mobile version of your site is what Google indexes and ranks.

26. Site is fully functional on mobile without horizontal scrolling

• Test with Google's Mobile-Friendly Test
• Check at multiple mobile viewport sizes (320px to 430px wide)
• All interactive elements (buttons, forms, navigation) work correctly on touch screens

27. Viewport meta tag is correctly set

<meta name="viewport" content="width=device-width, initial-scale=1">

This tag is required for proper mobile rendering. Without it, mobile browsers render the page at desktop width and scale it down, making it essentially unreadable.

28. Touch targets are sized appropriately for mobile

• Minimum touch target size is 48×48 pixels (Google recommendation)
• At least 8px spacing between adjacent touch targets
• No text too small to read without zooming (minimum 12pt / 16px)

29. Hreflang is correctly configured for multilingual sites

• Every alternate language URL has a corresponding hreflang tag
• Include x-default for the fallback language
• Hreflang tags are bidirectional — each page references all other variants including itself

30. Redirect from non-preferred to preferred URL variants

• HTTP → HTTPS
• www → non-www (or vice versa)
• Trailing slash to no trailing slash (or vice versa)
• All redirects are 301 (permanent)