You can write the best article on a topic, earn a few good links and still watch it sit on page four. When that happens, the problem is often not the content. It is something underneath the page that makes it hard for Google to find, load or understand.
That is what technical SEO deals with. It is less visible than blogging or link building, but when something breaks here, it can hold back every page on your site at once. These are the issues we find most often when we audit websites.
1. Pages That Google Can’t Index
The most basic check is also the one people skip. If a page isn’t in Google’s index, it can’t rank for anything.
Common causes include:
- A noindex tag left on from when the site was in development
- A robots.txt file that blocks important folders
- Pages that are only reachable through search boxes or filters with no normal link
- Pages Google has crawled but decided aren’t worth indexing
Open the Pages report in Google Search Console. It lists what is indexed, what isn’t and why. Anything important sitting in the “not indexed” list needs attention first.
2. Slow Loading and Poor Core Web Vitals
Google measures real user experience through Core Web Vitals. The three main measures are how quickly the main content loads (Largest Contentful Paint, ideally under 2.5 seconds), how quickly the page reacts when someone taps or clicks (Interaction to Next Paint, ideally under 200 milliseconds) and how much the layout jumps around while loading (Cumulative Layout Shift, ideally under 0.1).
Speed alone won’t push a weak page to the top, but a slow site loses both rankings and visitors when competing pages are close in quality. The usual fixes are compressing and resizing images, removing unused plugins and scripts, using caching and a CDN, and choosing hosting that can handle your traffic.
3. Broken Links and Redirect Chains
Over time, pages get deleted, URLs change and links point to places that no longer exist. Each broken link is a dead end for visitors and for Google’s crawler.
Redirect chains are a quieter version of the same problem. Page A redirects to B, which redirects to C, which redirects to D. Each hop slows things down and can dilute the value passing through. Point every redirect straight to the final destination.
A crawler like Screaming Frog or the site audit tool in Ahrefs or Semrush will find both problems in a few minutes.
4. Duplicate Content and Missing Canonicals
Duplicate content isn’t a penalty, but it does confuse Google about which page to rank. It often happens by accident.
- The same page loads with and without www, or with and without a trailing slash
- Online stores create several URLs for one product through filters and sorting
- Printer-friendly or tracking-parameter versions of pages get indexed
- Location pages copied with only the city name swapped
Canonical tags tell Google which version is the main one. Pick one preferred URL format, redirect the rest to it, and make sure each page’s canonical tag points to itself unless it really is a copy.
5. A Messy Site Structure
If your best pages are buried five or six clicks from the homepage, Google treats them as less important. Visitors struggle to find them too.
Aim for a structure where every important page can be reached within three clicks. Group related content under clear categories, link between related articles, and make sure your main services are in the navigation. Pages with no internal links pointing to them, often called orphan pages, rarely perform well.
6. Missing or Outdated XML Sitemap
A sitemap is a list of the pages you want Google to find. It doesn’t guarantee indexing, but it helps, especially for new or large sites.
Check that your sitemap only includes live, indexable pages. We regularly find sitemaps full of redirected URLs, deleted pages and test pages. Submit the clean version in Search Console and check back for errors.
7. Mobile Problems
Google uses the mobile version of your site for ranking. If content, links or structured data exist on desktop but are hidden or missing on mobile, Google may not see them at all.
Look at your key pages on an actual phone. Check that text is readable without zooming, buttons are easy to tap, nothing overflows the screen and the same content appears as on desktop.
8. No Structured Data
Structured data, or schema markup, is code that tells search engines exactly what a page is about. It can help your listings show extra details like star ratings, prices, FAQs or business information.
At a minimum, most business sites benefit from Organization or LocalBusiness schema. Online stores should use Product schema, and articles should use Article schema. Test your markup with Google’s Rich Results Test before and after publishing.
9. HTTPS and Mixed Content Issues
Almost every site now runs on HTTPS, but some still load images or scripts over plain HTTP. Browsers may flag this as not secure, which hurts trust. Make sure every resource loads over HTTPS and that all old HTTP URLs redirect properly.
10. AI Crawlers and the llms.txt Question
AI search has added a new layer to technical SEO. Tools like ChatGPT and Perplexity use their own crawlers, such as OAI-SearchBot and PerplexityBot. Some security plugins and CDN settings now block these bots by default, which means your site may be invisible to those tools without you ever deciding that. Check your robots.txt file and your firewall or CDN bot settings, and make a deliberate choice about which crawlers you allow.
For Google, the rule is simpler. AI Overviews and AI Mode are part of Google Search, so if Googlebot can crawl and index your pages, they are eligible. The separate Google-Extended setting only controls whether your content is used to train Google’s Gemini models, not whether you appear in Search.
You may also have heard that you need an llms.txt file. In June 2026 Google updated its guidance to say plainly that Search doesn’t use llms.txt or any other special AI file, including for its AI features. An Ahrefs study the same month found that the vast majority of llms.txt files received no bot visits at all. It won’t hurt to have one, but it isn’t a shortcut. Clean crawling, fast pages and clear content still do the heavy lifting.
How Often Should You Check?
Run a full technical audit at least twice a year and after any major change, such as a redesign, platform migration or new theme. In between, keep an eye on Search Console. It will usually warn you about indexing and performance problems before they cause a big drop.
Final Thoughts
Technical SEO isn’t glamorous, but it is the foundation everything else sits on. Fixing a handful of these issues can lift rankings across an entire site, because every page benefits at once.
If you suspect something under the hood is holding your site back, The Big Growth can run a technical SEO audit and give you a clear, prioritised list of fixes. We handle the fixes too if you would rather not touch the code. Request your free growth plan to get started.
Frequently Asked Questions
What is technical SEO in simple terms?
It is the work that makes sure search engines can find, load, understand and index your website properly. It covers things like speed, site structure, indexing, redirects and structured data.
Can I do technical SEO myself?
Many checks are free and beginner-friendly using Google Search Console and PageSpeed Insights. Fixing deeper issues, such as server settings, code-level speed problems or large-scale redirects, usually needs a developer.
How long does it take to see results from technical SEO fixes?
Some fixes, such as removing an accidental noindex tag, can show results within days once Google recrawls the page. Wider improvements like speed and structure usually show their effect over several weeks.
