Technical SEO is the foundation everything else sits on. Great content and strong backlinks won't save a site that Google can't properly crawl, render, or index. This checklist covers 8 core areas, ordered by impact — use it for new site audits, quarterly reviews, or pre-launch sign-offs.
1. Crawlability & Indexation
If Google can't crawl or index your pages, nothing else matters. Start every audit here.
Visit yourdomain.com/robots.txt and verify no critical URLs or directories are disallowed. A single bad Disallow rule can kill crawling of your entire site.
GSC → Sitemaps. Status should be Success with no errors. Resubmit after major content changes or URL restructures.
Check for meta name="robots" content="noindex" on pages that should rank. Screaming Frog → Response Codes → Filter by noindex surfaces these instantly.
Paginated pages, faceted navigation, session IDs, and UTM parameter URLs consume crawl budget. Block or noindex these to focus Googlebot on pages that matter.
Links passing through 301→301→301 waste crawl budget and dilute PageRank. Always link directly to the final destination URL.
Don't include noindex pages, redirects, or non-canonical URLs. This confuses Google about your indexation intent and wastes processing.
2. Core Web Vitals
CWV are confirmed ranking signals. LCP has the highest correlation with ranking changes after Google core updates — fix it first.
Check GSC → Core Web Vitals. Field data — real user measurements — is what Google uses for rankings, not PageSpeed Insights lab scores.
Add <link rel="preload" as="image" href="hero.jpg"> in <head> for your above-the-fold image. Single highest-impact LCP fix for most sites.
Interaction to Next Paint replaced FID in 2024. High INP is caused by heavy JavaScript blocking the main thread. Diagnose with Chrome DevTools → Performance.
Usually caused by images without dimensions, font swaps, or ads loading above content. Set explicit width/height on all media elements to prevent layout shifts.
Slow TTFB means slow hosting, no CDN, or unoptimised server rendering. Add a CDN or switch to edge hosting if TTFB consistently exceeds 800ms.
30–50% smaller than JPEG/PNG with no visible quality loss. Directly improves LCP and page speed scores at zero quality cost.
3. URL Structure & Canonicalization
Pick one version and permanently redirect the other. Both versions serving content simultaneously creates duplicate pages at scale across your entire site.
<link rel="canonical" href="https://yourdomain.com/page/"> should be on every page, pointing to the exact URL you want ranked.
A 302 temporary redirect doesn't pass full PageRank and signals the change is not permanent. Always use 301 for HTTPS migration.
/page/ and /page should only serve at one URL — the other must 301 redirect. Inconsistency creates duplicate versions of every page on your site.
Google treats hyphens as word separators but underscores as word joiners. /my-page ranks for "my page" — /my_page does not.
4. Mobile SEO
Google uses mobile-first indexing for all sites. Your mobile version is your primary SEO version — not desktop.
<meta name="viewport" content="width=device-width, initial-scale=1"> must be in <head>. Missing this causes mobile rendering to fail completely.
With mobile-first indexing, content hidden on mobile won't be indexed by Google. Ensure all important content renders on mobile.
Buttons and links that are too small create poor UX signals. Google's Mobile Usability report in GSC flags these as specific issues.
Full-screen popups blocking content on page load are a negative ranking signal on mobile since 2017. Use banners or time-delayed popups instead.
5. On-Page Technical Elements
Title tags should be 50–60 characters, contain the primary keyword, and be unique site-wide. Duplicates confuse Google about which page to rank for which query.
Not a direct ranking factor but well-written descriptions improve click-through rates from SERPs. Keep them 120–155 characters with a clear value proposition.
Multiple H1s send mixed signals about page topic. One clear H1 matching search intent is standard for every well-optimised page.
Alt text helps Google understand image context and is a Google Images ranking signal. Write descriptive alt text — not keyword-stuffed strings.
"Click here" passes no topical signal. "Technical SEO checklist" passes a strong one. Anchor text tells Google what the linked page is about.
Broken links waste crawl budget and signal poor site maintenance. Run a Screaming Frog crawl monthly to catch and fix them quickly.
6. Schema Markup
Structured data doesn't directly boost rankings but enables rich results — star ratings, FAQ accordions, breadcrumbs — that significantly improve SERP click-through rates.
Include headline, author, datePublished, dateModified, and publisher. Helps Google classify your content correctly in its knowledge graph.
Include name, url, logo, and sameAs (your social profile links). Helps Google understand your brand entity and build associations.
Breadcrumb rich results show your site hierarchy in SERPs. They improve CTR and user understanding of your site structure.
Test at search.google.com/test/rich-results. Validation errors prevent rich results from appearing even when schema intent is correct.
7. JavaScript & Rendering
Google treats JavaScript rendering as a two-stage process. Content appearing only after JS execution may be crawled days or weeks later than static HTML.
GSC → URL Inspection → Test Live URL → View Tested Page → Screenshot. Compare the rendering against what a browser user sees — differences signal problems.
CSS and JS blocking above-the-fold rendering delay LCP. Inline critical CSS and defer non-critical JS to avoid this.
Analytics, chat widgets, and ad scripts should use async or defer attributes to avoid blocking page rendering and hurting CWV scores.
8. Security & HTTPS
An expired SSL shows a browser security warning that kills traffic immediately. Enable auto-renewal or set calendar reminders 30 days before expiry.
HTTP images, scripts, or stylesheets on an HTTPS page trigger browser warnings. Scan with Why No Padlock to find and fix mixed content issues.
Not a direct ranking factor but affects trust signals. Test at securityheaders.com and implement the recommended headers for your stack.
Start with any Critical items in your GSC Coverage and Core Web Vitals reports first — those are issues Google has already flagged against your specific site. Work through this checklist top to bottom after that. Most sites see measurable ranking movement after fixing crawlability + LCP alone.
Recommended Tools
| Tool | Best For | Cost |
|---|---|---|
| Google Search Console | Crawl errors, CWV field data, index coverage, manual actions | Free |
| Screaming Frog | Full site crawl, broken links, redirect chains, duplicate tags | Free up to 500 URLs |
| PageSpeed Insights | CWV lab data, LCP element ID, specific fix recommendations | Free |
| Chrome DevTools | INP analysis, render-blocking JS, network waterfall | Free |
| Rich Results Test | Schema validation and rich result eligibility | Free |
| Ahrefs Site Audit | Comprehensive crawl with prioritised issue scoring | Paid |
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