Technical SEO Checklist: Everything Your Developer Needs to Know

*Pillar page -- comprehensive resource*

Technical SEO is the foundation everything else sits on. If your site is slow, insecure, or hard for Google to crawl, no amount of content or link building will save you.

This checklist covers every technical SEO factor that matters in 2026. Use it yourself, hand it to your developer, or let our audit check everything automatically.

Speed & Performance

Google measures your site speed with Core Web Vitals. These are the thresholds:

| Metric | What It Measures | Good | Poor | |--------|-----------------|------|------| | LCP (Largest Contentful Paint) | How fast main content loads | < 2.5s | > 4.0s | | INP (Interaction to Next Paint) | How fast site responds to clicks | < 200ms | > 500ms | | CLS (Cumulative Layout Shift) | How much content moves during load | < 0.1 | > 0.25 |

Speed Checklist

[ ] Images compressed (WebP format, appropriate dimensions)

[ ] Lazy loading on below-fold images (`loading="lazy"`)

[ ] Hero/above-fold images load immediately (NOT lazy loaded)

[ ] CSS minified and critical CSS inlined

[ ] JavaScript deferred where possible (`defer` or `async`)

[ ] No render-blocking resources in ``

[ ] Browser caching enabled (cache headers on static assets)

[ ] Compression enabled (gzip or brotli)

[ ] HTTP/2 or HTTP/3 enabled

[ ] Total page weight under 3MB (ideal: under 1.5MB)

[ ] Server response time (TTFB) under 600ms

[ ] CDN for static assets (if serving geographically diverse audience)

[ ] Width and height attributes on all `` tags (prevents CLS)

[ ] `font-display: swap` on web fonts (prevents CLS from font loading)

[ ] No excessive third-party scripts (analytics, chat widgets, social embeds)

Security

HTTPS

[ ] SSL certificate installed and valid

[ ] Certificate covers all subdomains in use

[ ] HTTP to HTTPS redirect in place (301, not 302)

[ ] No mixed content (HTTP resources on HTTPS pages)

[ ] HSTS header set (forces HTTPS permanently)

Security Headers

[ ] Strict-Transport-Security (HSTS)

[ ] X-Frame-Options (prevent clickjacking)

[ ] X-Content-Type-Options (prevent MIME sniffing)

[ ] Content-Security-Policy (prevent XSS)

[ ] Referrer-Policy (control referrer data)

[ ] Permissions-Policy (control browser features)

Platform Security

[ ] CMS and plugins up to date

[ ] CMS version not exposed in source code

[ ] Admin pages not publicly accessible (or at least not indexed)

[ ] Backup system in place

Crawlability & Indexing

robots.txt

[ ] robots.txt exists at /robots.txt

[ ] Not blocking important pages

[ ] Not blocking CSS, JS, or images (Google needs to render your pages)

[ ] Sitemap URL referenced

[ ] No accidental Disallow: /

XML Sitemap

[ ] Sitemap exists and is valid XML

[ ] Referenced in robots.txt

[ ] Submitted to Google Search Console

[ ] Contains only indexable, canonical URLs

[ ] No 404s, redirects, or noindex pages in sitemap

[ ] Lastmod dates are accurate (not all the same)

[ ] Under 50,000 URLs per sitemap (use sitemap index if larger)

Indexing

[ ] Key pages are indexed (check: site:yourdomain.com in Google)

[ ] No important pages blocked by noindex

[ ] Canonical tags present and correct on all pages

[ ] Self-referencing canonicals on primary pages

[ ] www and non-www resolve to one version (other redirects)

[ ] No duplicate content issues (same content at different URLs)

Internal Links

[ ] Navigation uses standard HTML `` tags (not JavaScript-only)

[ ] All important pages reachable within 3-4 clicks from homepage

[ ] No orphan pages (pages with no internal links to them)

[ ] Breadcrumb navigation present with BreadcrumbList schema

[ ] Logical site structure (homepage > categories > pages)

Redirects

- [ ] No redirect chains (A > B > C; should be A > C directly)

[ ] No redirect loops

[ ] All redirects use 301 (permanent) unless intentionally temporary

[ ] HTTP > HTTPS redirect is single hop

[ ] www > non-www (or vice versa) is single hop

[ ] Old domain URLs redirect page-to-page (not all to homepage)

[ ] Google Search Console Change of Address used (if domain changed)

Mobile

- [ ] Viewport meta tag present: ``

[ ] Text readable without zooming (16px minimum base font)

[ ] Tap targets 48px minimum size, 8px minimum spacing

[ ] No horizontal scrolling required

[ ] Content identical on mobile and desktop

[ ] Images scale responsively

[ ] Forms work on mobile

[ ] No intrusive interstitials (full-screen popups on mobile)

Structured Data (Schema Markup)

- [ ] JSON-LD format used (Google's preferred format)

[ ] No errors in Rich Results Test

[ ] Organization schema on homepage

[ ] LocalBusiness schema on location pages (for local businesses)

[ ] BreadcrumbList schema matching visual breadcrumbs

[ ] FAQPage schema on FAQ content

[ ] Article schema on blog posts

[ ] Product schema on product pages (e-commerce)

[ ] WebSite schema with SearchAction (if site has search)

[ ] Structured data matches visible content (don't mark up hidden info)

JavaScript SEO

- [ ] Critical content visible in raw HTML (view source, not just inspect)

[ ] Internal links are crawlable HTML `` tags

[ ] Meta tags in initial HTML response

[ ] Structured data in initial HTML (or rendered by JS Google can execute)

[ ] No content behind click-only events

[ ] Test with URL Inspection Tool in Search Console (how Googlebot renders your page)

International SEO (If Applicable)

- [ ] hreflang tags for multi-language/multi-region pages

[ ] Language declared in HTML lang attribute

[ ] Consistent geo-targeting (hreflang + Search Console + content)

[ ] No duplicate content across language versions

Tools to Check Everything

| Tool | What It Checks | Cost | |------|---------------|------| | Google PageSpeed Insights | CWV, speed, best practices | Free | | Google Search Console | Indexing, CWV, crawl errors, search performance | Free | | Google Lighthouse (Chrome DevTools) | Full technical audit | Free | | Rich Results Test | Structured data validation | Free | | Mobile-Friendly Test | Mobile responsiveness | Free | | SEO Rank Masters | All of the above + Google Maps + AI search + competitors | From GBP 29 |

How to Prioritise

1. Fix anything that prevents indexing (noindex on important pages, robots.txt blocking, broken redirects) 2. Fix speed issues (image compression, lazy loading, render-blocking resources) 3. Fix security (HTTPS, security headers) 4. Fix mobile issues (viewport, tap targets, responsive images) 5. Add structured data (LocalBusiness, Organization, FAQ) 6. Clean up redirects (eliminate chains, fix 302s to 301s) 7. Improve internal linking (connect related pages, fix orphans)

Each level builds on the one below. Don't skip ahead.

*Get your complete technical SEO audit with scores, issues, and prioritised fixes. [SEO Rank Masters](https://seorankmasters.com) -- from GBP 29.*

[Core Web Vitals Explained](/blog/16-core-web-vitals-explained)

[What Are Security Headers and Why Google Cares?](/blog/06-security-headers-seo)

[Schema Markup for Your Business](/blog/17-schema-markup-business)

[5 SEO Quick Wins Any Business Owner Can Do Today](/blog/04-seo-quick-wins)

[SEO Audit Checklist: Everything We Check](/blog/10-seo-audit-checklist)