Technical SEO is the plumbing. When it works, nobody notices; when it fails, nothing else you do in content or links can drain through. A technical audit is how you find the blockages before they cost you rankings and enquiries.
This is a full technical SEO audit checklist for 2026. For each item it explains what it means, why it matters and how to check it. You can run most of it with free tools — Google Search Console, PageSpeed Insights and a crawler like Screaming Frog (free up to 500 URLs). Work top to bottom; the earlier items gate the later ones.
Crawlability and indexing
If search engines cannot crawl and index a page, nothing else about it matters.
Check what is actually indexed
In Google Search Console, open the Pages report under Indexing. It splits your URLs into indexed and not-indexed, with reasons: "Crawled – currently not indexed", "Discovered – currently not indexed", "Excluded by noindex tag", "Duplicate without user-selected canonical" and so on.
Look for two problems. First, important pages that are not indexed — a money-making service page sitting in "Discovered – currently not indexed" is invisible. Second, junk that is indexed — filtered URL variants, internal search results, staging pages. A quick sanity check is a site:yourdomain.co.uk search; if the count is wildly higher than your real page count, you have index bloat.
robots.txt
Your robots.txt file (at yourdomain.co.uk/robots.txt) tells crawlers where they may go. The classic disaster is a Disallow: / left over from a staging environment, which blocks the entire site. Read the file line by line and confirm you are not accidentally blocking CSS, JavaScript or important sections. Remember that robots.txt blocks crawling, not indexing — a blocked URL can still appear in results without a description, so use noindex for genuine exclusion.
XML sitemaps
Your XML sitemap lists the URLs you want indexed. Check that it exists, is referenced in robots.txt, contains only canonical, indexable, 200-status URLs, and excludes redirects, noindexed and 404 pages. Submit it in Search Console and watch the coverage. A sitemap stuffed with redirects and dead links wastes crawl budget and signals a poorly maintained site.
Site architecture and internal linking
Architecture is how pages relate to each other. A flat, logical structure helps crawlers and users.
The three-click principle
Any important page should be reachable within roughly three clicks of the homepage. Deeply buried pages get crawled less and rank worse. Map your structure: homepage to category to page. If key service pages sit five clicks deep behind pagination and filters, restructure with clearer navigation and internal links.
Internal links and orphan pages
Orphan pages — pages with no internal links pointing to them — are hard for Google to find and value. Crawl the site and cross-reference against your sitemap and analytics to spot them. Then link to important pages from relevant content and navigation. Internal linking also passes ranking signals, so link from strong pages to the ones you want to lift, using descriptive anchor text rather than "click here".
Core Web Vitals and page experience
Core Web Vitals are Google's measurable page-experience metrics, and they remain a ranking factor in 2026.
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LCP (Largest Contentful Paint): how quickly the main content loads. Aim under 2.5 seconds.
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INP (Interaction to Next Paint): responsiveness to input, which replaced FID in 2024. Aim under 200 milliseconds.
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CLS (Cumulative Layout Shift): visual stability. Aim under 0.1.
Check the Core Web Vitals report in Search Console, which uses real-world field data, then diagnose individual pages in PageSpeed Insights. Prioritise your highest-traffic and highest-value templates. We cover the fixes in depth in our dedicated Core Web Vitals guide, but common wins are compressing images, deferring unused JavaScript and reserving space for images and ads to stop layout jumping.
Mobile
Google indexes the mobile version of your site, so mobile is not a secondary concern — it is the concern. Check that content, links and structured data present on desktop are also present on mobile. Test tap-target spacing, font legibility and that nothing important hides behind interstitials. Use Chrome's device emulation and, more importantly, load your key pages on a real mid-range Android phone on 4G. That is closer to how much of your UK audience actually experiences the site than a fast office connection suggests.
HTTPS and security
Every page should load over HTTPS with a valid certificate. Check for mixed content — HTTPS pages that pull images, scripts or stylesheets over insecure HTTP — which browsers flag and which undermines the secure padlock. Confirm that HTTP versions redirect to HTTPS with a 301. Verify your certificate is current and set a renewal reminder; an expired certificate throws a full-page browser warning that stops visitors dead.
Canonicals, duplicates and redirects
Canonical tags
A canonical tag tells Google which version of similar or duplicate pages is the master. Check that each page's canonical points to itself (for the preferred version) or to the correct master. Watch for pages canonicalising to the homepage by mistake, or to a redirected or noindexed URL — both send confused signals.
Redirects
Audit your redirects. Use 301s for permanent moves. Eliminate redirect chains (A to B to C), which waste crawl budget and slow users, by pointing each redirect straight to the final destination. Fix internal links that point at redirected URLs so they hit the destination directly. Find broken internal links (404s) in your crawl and either restore the page or redirect it to the most relevant live equivalent.
Parameter and duplicate handling
Faceted navigation, session IDs and tracking parameters spawn duplicate URLs. Decide how each should be handled — canonicalised, noindexed or blocked — so you are not asking Google to crawl thousands of near-identical variants.
Structured data
Structured data (schema markup) helps search engines and AI systems understand your content and can unlock rich results. Validate your markup with the Rich Results Test and Schema.org validator. Check that the types you use are appropriate and complete, that the data in the markup matches what is visible on the page, and that you are not marking up information that is not shown to users, which breaches guidelines. Priorities for most UK businesses are Organization, LocalBusiness, Article, Product, FAQ and BreadcrumbList.
Log file analysis
Server log files record every request a crawler makes, and they reveal what Googlebot actually does rather than what you assume. Export a sample of logs and look at which URLs get crawled most, whether crawl budget is being spent on junk (parameter URLs, old redirects), whether important pages are crawled rarely, and the status codes bots receive. For large sites this is one of the highest-value checks; for a small brochure site it matters less. If your site has under a few hundred pages, you can usually skip deep log analysis and spend the time elsewhere — be honest about where the effort pays off.
JavaScript rendering
If your site relies on JavaScript to build content — many React, Vue and Angular sites do — confirm Google can render it. Use the URL Inspection tool in Search Console and view the rendered HTML: is your main content, are your links, are your meta tags present after rendering? If key content only appears after client-side JavaScript that Google struggles with, consider server-side rendering or pre-rendering. A common failure is navigation links built as JavaScript click handlers rather than real anchor tags (<a href>), which crawlers cannot follow.
AI-crawler considerations for 2026
Search now includes AI Overviews, ChatGPT, Perplexity and other systems that cite web sources. Getting cited by these is increasingly part of technical SEO.
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Decide on AI crawler access. Bots like GPTBot, ClaudeBot, PerplexityBot and Google-Extended can be allowed or blocked in robots.txt. Blocking them protects content but removes you from AI answers that could send referrals or build authority. This is a business decision, not a purely technical one — make it deliberately rather than by accident.
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Make content machine-readable. Clear headings, plain-language answers near the top of pages, and thorough structured data all help AI systems extract and cite you accurately.
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Keep facts consistent. AI systems cross-reference. Inconsistent details across your pages and profiles reduce the chance of being cited confidently.
Where NetTrackers fits
A technical audit is only useful if the fixes get implemented, and that is where many audits stall. Our SEO audits come with a prioritised action plan, and because we also do web design and development in-house, we can actually make the changes rather than handing you a PDF. For ongoing work, our organic SEO and AI SEO services keep the technical foundation sound as the search landscape shifts.
Everything is month-to-month with no long contracts. Book a free strategy call or start with a free SEO audit.
Frequently asked questions
How often should I run a technical SEO audit?
A full audit once or twice a year for most sites, with lighter monthly checks of Search Console for new indexing or Core Web Vitals issues. Run a fresh audit after any major redesign or migration.
Do I need paid tools?
No, to start. Search Console, PageSpeed Insights and Screaming Frog's free tier cover most small and medium sites. Paid crawlers and log analysers help on large sites.
Should I block AI crawlers?
It depends on your goals. Blocking protects content but removes you from AI answers that increasingly drive visibility. Decide deliberately rather than leaving it to chance.
What is the most common serious technical issue you find?
Accidental noindex tags or robots.txt blocks left over from staging, quietly hiding important pages. It is worth checking these first.
Is technical SEO a one-off job?
No. Sites change, plugins update, content gets added. Technical health drifts without periodic review, so treat it as maintenance rather than a single project.