Technical SEO Audit Checklist: 25 Issues That Are Killing Your Rankings

Why technical SEO is the foundation everything else depends on

You can write the best content in your industry and earn hundreds of backlinks, but if your site has fundamental technical issues — pages that can't be crawled, duplicate content confusing Google, a sitemap pointing to 404s — your rankings will underperform relative to the investment. Technical SEO is the plumbing that allows content and authority to do their jobs.

A full technical audit should be run when: you launch a new site, you complete a redesign or migration, your rankings drop unexpectedly, or as an annual health check. Many businesses only discover technical issues when something goes wrong — the audit is how you find and fix them before they cost you traffic.

Crawlability and indexation (issues 1–8)

1. robots.txt blocking important pages — Review your robots.txt and ensure you're not accidentally disallowing /wp-admin, /wp-content/uploads or entire subdirectories that contain ranking content. A misconfigured robots.txt after a site migration is the most common cause of sudden traffic loss.

2. Incorrect noindex tags — Check that your key pages (services, blog posts, landing pages) do not have 'noindex' in their meta robots tag. Staging site noindex settings left in place after launch affect entire sites.

3. Orphan pages — Pages with no internal links pointing to them are invisible to crawlers navigating your site's link graph. Use a crawler (Screaming Frog, Sitebulb) and compare against your sitemap to identify orphans.

4. Broken internal links (4xx errors) — Every 404 internal link wastes crawl budget and creates a dead end in your site architecture. Export all internal links and filter for non-200 responses monthly.

5. XML sitemap issues — Your sitemap should contain only canonical, indexable URLs returning 200 status. Remove redirected URLs, noindex pages and 404s from your sitemap. Resubmit to Google Search Console after every significant site change.

6. Crawl depth — Key pages should be reachable within 3–4 clicks from the homepage. Pages buried 6+ levels deep in site architecture receive less crawl budget and lower PageRank flow. Review your site architecture and flatten where possible.

7. Pagination handling — Paginated content (/blog?page=2) must be accessible to Googlebot and either allowed to index or canonicalised appropriately. Infinite scroll implementations often break crawler access entirely.

8. Canonical tag accuracy — Every page should have a self-referencing canonical tag, and every duplicate or near-duplicate page should have a canonical pointing to the preferred URL. Incorrect canonical chains (A canonicals to B, B canonicals to C) confuse crawlers.

Duplicate content and on-page signals (issues 9–15)

9. Duplicate page titles and meta descriptions — Every page needs a unique, keyword-targeted title tag (50–60 characters) and meta description (150–160 characters). Templated CMS pages frequently generate duplicates at scale.

10. Thin content pages — Pages with under 300 words of substantive content that serve no unique informational purpose dilute your site's overall quality signals. Consolidate, expand or noindex thin pages.

11. Missing or duplicate H1 tags — Each page should have exactly one H1 containing its primary keyword. Multiple H1s on a page confuse crawlers; missing H1s waste a key relevance signal.

12. URL parameter duplication — Tracking parameters, session IDs and filter facets create thousands of duplicate URLs if not handled with canonical tags or URL parameter tools in Search Console.

13. Hreflang errors — International sites with hreflang markup frequently have misconfigured tags: missing return tags, wrong language codes, or hreflang pointing to non-indexable URLs. Validate using Screaming Frog's hreflang auditor.

14. Internal link anchor text — Vary your internal link anchor text and ensure key pages receive relevant, descriptive anchor text from internal links rather than generic 'click here' or URL-based anchors.

15. Image alt text — Every image should have a descriptive, relevant alt attribute. Missing alt text misses an accessibility requirement and a keyword signal that accumulates meaningfully at scale.

Site speed and Core Web Vitals (issues 16–20)

16. Server response time (TTFB) above 200ms — If your Time to First Byte exceeds 200ms, investigate hosting infrastructure, server-side caching and database query performance before optimising front-end assets.

17. Unoptimised images — Images are the most common cause of page weight and LCP issues. Compress all images to WebP/AVIF, declare explicit dimensions, lazy-load off-screen images and preload the hero/LCP image.

18. Render-blocking resources — Scripts and stylesheets in the `<head>` that prevent the page from rendering block LCP. Defer non-critical JavaScript, inline critical CSS and async-load third-party scripts.

19. Missing browser caching headers — Static assets (images, CSS, JavaScript) should be served with long-expiry Cache-Control headers so repeat visitors load them from cache rather than re-downloading. Most CDNs handle this automatically — verify they're configured.

20. No CDN or poor CDN configuration — A CDN (Cloudflare, Fastly, CloudFront) reduces TTFB and LCP for geographically distributed audiences. UK sites served from US servers and vice versa are a common performance issue.

Structured data and schema (issues 21–25)

21. Missing Organization schema — Every business website should have Organization (or LocalBusiness) schema on the homepage declaring the company name, URL, logo, contact information and social profiles. This feeds the Knowledge Panel and entity recognition in AI engines.

22. Missing BreadcrumbList schema — Breadcrumb structured data enables rich results in search and helps Google understand your site architecture. Implement on all interior pages.

23. Missing or invalid FAQPage schema — FAQPage schema on service and content pages significantly increases eligibility for rich results and AI citation. Validate all schema using Google's Rich Results Test.

24. Product schema errors — E-commerce sites with incomplete or invalid Product schema miss rich results (price, availability, rating) that significantly improve CTR. Common errors: missing aggregateRating, invalid price format, incorrect availability values.

25. Schema validation errors — Schema that is syntactically correct but semantically wrong (missing required properties, wrong value types) generates validation errors in Google's Rich Results Test and Search Console's Enhancement reports. Run validation after every schema implementation or update.

Running and acting on the audit

Tools for a complete technical audit: Screaming Frog SEO Spider (crawl analysis), Google Search Console (index coverage, CWV, manual actions), PageSpeed Insights and Chrome DevTools (performance), Google's Rich Results Test (schema validation), Ahrefs or Semrush (backlink and redirect analysis).

Prioritise fixes by impact and effort. A misconfigured robots.txt blocking your entire site is an emergency. A few missing image alt texts on blog posts are a low-priority cleanup task. Build a prioritised fix backlog with severity ratings and assign to the appropriate person — developer for technical items, content team for on-page signals.

Schedule quarterly re-crawls. Technical SEO health degrades over time: content gets added, plugins get updated, templates get modified. What was clean six months ago may have new issues today. Make the audit a regular process, not a one-time event.