Technical SEO Checklist 2026: 50+ Critical Points

A complete, prioritised technical SEO checklist for 2026: crawlability, site architecture, Core Web Vitals, mobile, HTTPS, international, schema. Print it, work through it.

Technical SEO is the foundation everything else rests on. The cleanest content with the best backlinks won't rank if your site can't be crawled, indexed, and rendered. This is the checklist we run on every new client audit.

1. Crawlability (10 checks)

• ✓ robots.txt exists at root and isn't blocking critical paths
• ✓ XML sitemap exists and is referenced in robots.txt
• ✓ Sitemap submitted to Google Search Console and Bing Webmaster Tools
• ✓ No noindex on pages you want ranked (check meta + HTTP headers)
• ✓ No nofollow on internal links to important pages
• ✓ Crawl budget healthy — Search Console shows server response < 600ms
• ✓ No infinite crawl traps (faceted URLs, calendar pages, etc.)
• ✓ Pagination uses semantic HTML or self-referential canonicals
• ✓ JavaScript-rendered content is also in the initial HTML (or use SSR/SSG)
• ✓ Mobile and desktop versions are equivalent (mobile-first indexing)

2. Site architecture (8 checks)

• ✓ Logical, shallow hierarchy — every page reachable in ≤ 3 clicks from home
• ✓ URL structure clean and descriptive: /category/subcategory/page
• ✓ No deeply nested URLs (> 4 levels) for important content
• ✓ Breadcrumbs present and marked up with BreadcrumbList schema
• ✓ Internal linking distributes PageRank to priority pages
• ✓ Orphan pages identified and either deleted or linked to
• ✓ Topic clusters created for major themes (hub + supporting pages)
• ✓ Footer / sitemap navigation links to deep pages

3. Indexing & canonicals (6 checks)

• ✓ Every canonical URL is self-referential (or points to the right master)
• ✓ No conflicting canonical signals (canonical vs hreflang vs noindex)
• ✓ HTTPS canonical (not HTTP) on every page
• ✓ Trailing slash policy consistent (with or without — pick one)
• ✓ Lowercase URLs only (no /About alongside /about)
• ✓ www vs non-www: pick one, 301 the other

4. Core Web Vitals (8 checks)

• ✓ LCP < 2.5s — Largest Contentful Paint on the slowest tested page
• ✓ INP < 200ms — Interaction to Next Paint (replaces FID in 2024+)
• ✓ CLS < 0.1 — Cumulative Layout Shift
• ✓ Images served as WebP/AVIF with width and height attributes
• ✓ Above-the-fold images use fetchpriority="high"
• ✓ Below-the-fold images use loading="lazy"
• ✓ Critical CSS inlined; non-critical CSS deferred
• ✓ Third-party scripts loaded with async or defer

5. Mobile optimisation (5 checks)

• ✓ Mobile-first viewport meta tag present
• ✓ Tap targets ≥ 48px
• ✓ Font size ≥ 16px on body text
• ✓ No horizontal scroll at 360px viewport
• ✓ Mobile Friendly Test passes (Google's tool)

6. HTTPS & security (6 checks)

• ✓ HTTPS everywhere — no mixed-content warnings
• ✓ HSTS header set with at least 1-year max-age
• ✓ Valid SSL certificate (no expiry warnings)
• ✓ Security headers: X-Content-Type-Options, X-Frame-Options, Referrer-Policy, Permissions-Policy
• ✓ CSP header configured (even if permissive)
• ✓ No exposed admin paths or config files

7. Schema markup (6 checks)

• ✓ Organization schema on homepage with logo + sameAs
• ✓ WebSite schema with SearchAction (for sitelinks search box)
• ✓ BreadcrumbList on every non-home page
• ✓ Article schema on blog posts (with author, datePublished, dateModified)
• ✓ Product / Service / FAQPage where applicable
• ✓ All schema validated against Google's Rich Results Test

8. International SEO (5 checks — if applicable)

• ✓ hreflang tags on every page with language/country variants
• ✓ hreflang="x-default" set for the fallback version
• ✓ Each version is reciprocally linked (A → B and B → A)
• ✓ Separate URLs for each language (subdir, subdomain, or ccTLD — pick one)
• ✓ Geo-targeting configured in Search Console for ccTLDs not auto-detected

9. Images & media (4 checks)

• ✓ Descriptive filenames (handmade-leather-bag-berlin.jpg not IMG_4827.jpg)
• ✓ Alt text on every meaningful image (not decorative ones)
• ✓ Image sitemap submitted for image-heavy sites
• ✓ Video schema for video content (helps with Video carousel results)

10. Errors & redirects (5 checks)

• ✓ 404 errors monitored in Search Console; redirect or fix the top ones
• ✓ No redirect chains (A → B → C). Always single-hop.
• ✓ All 301s; avoid 302s for permanent moves
• ✓ Soft-404s identified and fixed (200 response on broken pages)
• ✓ Custom 404 page that helps users find what they need

How to use this checklist

Don't try to fix everything at once. Run through it once, mark each item as ✓ done / ⚠ needs work / ✗ broken. Then:

1. Fix all ✗ items first (these are actively hurting you).
2. Fix ⚠ items in order of estimated traffic impact.
3. Re-run the checklist quarterly.

Tools we use for each section

• Crawlability: Screaming Frog SEO Spider
• Core Web Vitals: Google PageSpeed Insights, CrUX dashboard
• Mobile: Google Mobile-Friendly Test, Chrome DevTools
• Schema: Google Rich Results Test, Schema.org validator
• Search Console: Coverage, Performance, Core Web Vitals reports
• Hreflang: Aleyda Solis's hreflang tags generator + Sitebulb

Want this done for you?

Our €50 SEO Starter Audit runs this exact checklist on your site (plus on-page, content, and backlink analysis) and delivers a prioritised PDF action plan within 48 hours.