Technical SEO: The Most Common Mistakes on Company Websites

Your content can be excellent – but if the technical foundation underneath it is broken, you'll still get found less often. That's exactly what technical SEO is about: the foundation that lets search engines and AI find, read, and understand your website in the first place.

In this article, we cover the most common technical SEO mistakes on company websites – and how to spot and fix them.

What Is Technical SEO?

Broadly speaking, there's a difference between content and technology. Content is what your visitors read. Technical SEO is everything working in the background to make sure that content loads fast, works on every device, and is easy for search engines to read.

Think of it like a building's technical infrastructure: you don't see it, but without working wiring and plumbing, even the most beautiful interior design doesn't help much. Technical SEO mistakes slow everything else down.

The Most Common Technical SEO Mistakes

These are the weak spots we see on company websites again and again.

1. Page Speed Is Too Slow

If a page takes too long to load, visitors leave before they've even seen anything – and search engines penalize that. How to spot it: if your site feels sluggish to you, it probably is. Page speed is one of the most important technical ranking factors there is.

2. Not Optimized for Mobile

Most visitors today come from smartphones. If your site is hard to use there, you lose both users and rankings. Test it by browsing through your website on your phone, unhurried, as a visitor would.

3. Pages Aren't Indexed Properly

What Google doesn't have in its index can't rank. Type site:yourdomain.com into Google Search – if noticeably fewer pages show up than expected, you have an indexing problem worth taking seriously.

4. Missing or Faulty HTTPS

Without valid encryption, browsers warn your visitors, and search engines downgrade the page. Check for the padlock icon in the address bar. If it's missing or a warning appears, you need to act quickly.

5. Broken Links and Redirects

Internal links leading nowhere, or chained redirects, frustrate users and make life harder for search engines. These issues tend to pile up unnoticed, especially after a relaunch or a domain move.

6. Missing Structured Data

Without clear markup, a machine has to guess what your content means – and that costs you visibility in both Google Search and AI search. To learn what's behind it, read structured data & schema markup explained simply.

7. Unclear Structure and Duplicate Content

If the same content is reachable under multiple URLs, or your site structure is confusing, search engines can't tell which version counts. That dilutes your visibility and is worth cleaning up.

Why These Mistakes Hurt Twice as Much

Technical SEO used to matter only for Google. Today, the same foundation matters just as much for AI search. An AI that can't load or read your page cleanly won't recommend you any more than Google will rank you well.

That's the bad news – and the good news at the same time. Fix the technical basics, and you improve both channels at once. Every mistake you fix pays off twice.

How to Find and Fix Technical Errors

You can check some of this yourself – our free DIY SEO check walks you through the essentials. For the deeper issues, like indexing, redirects, or structured data, you need some experience and a look under the hood.

The order matters: fix what affects the most visitors and is quick to solve first – page speed, mobile display, HTTPS. Then you can work through the more complex issues systematically.

Conclusion: The Invisible Foundation Matters Too

Technical SEO is rarely visible, but it's always effective. The most common mistakes – from page speed to indexing to missing structured data – cost you visibility on Google and in AI search alike. The good news: every one of these mistakes can be fixed.

Where your website stands technically can be analyzed clearly. That's exactly what we do at yes!devs with our free GEO/SEO audit: we check your technical foundation, your discoverability, and your visibility in AI search – and show you the three actions with the biggest impact.

Do you suspect there are technical issues on your website? Request your free GEO/SEO audit and find out where to start.