Technical SEO Explained: Loading Speed, Mobile, Security

Technical SEO makes sure that Google and AI assistants can read your website without problems and that visitors enjoy using it. The three most important points: the website must load quickly, work flawlessly on a smartphone and be reachable via a secure connection (HTTPS). On top of that, search engines must not be locked out by accident. That sounds technical – but you can check most of it yourself, in ten minutes and free of charge.

What is technical SEO?

When people think of SEO – search engine optimisation – most think of texts and search terms. But the best content is useless if the website loads too slowly, falls apart on a phone or cannot be read by Google at all. Technical SEO takes care of exactly this foundation.

An analogy: your content is the goods in the shop window. Technical SEO is the door, the lighting and the lock. If the door sticks, nobody gets in – no matter how good the goods are.

1. Loading speed: every second counts

Nobody likes waiting. If a page takes too long to load, visitors leave – often going straight back to Google and on to the next provider. Google measures the user experience with three metrics, the so-called Core Web Vitals (roughly: “key web values”):

You don't need to remember the abbreviations. What matters is that Google assesses whether your page feels fast and pleasant.

The most common brakes

• Images that are too large: A photo straight from the camera is often ten times larger than necessary. Modern formats such as WebP and a suitable size help enormously.

• Too many extensions: Every add-on program (in WordPress, a “plugin”) can slow the page down.

• Cheap hosting: The server your website lives on is sometimes simply too slow.

• Image sliders and autoplay videos: They look smart, but cost a lot of loading time.

2. Mobile-friendliness: the smartphone decides

Google now generally evaluates websites based on their smartphone version. Experts call this mobile-first indexing. What is missing or doesn't work on the phone practically doesn't count for Google.

A mobile-friendly website adapts automatically to any screen size. This is called responsive design. Make sure that:

• text is readable without zooming,

• buttons and links are big enough for a finger,

• nothing sticks out sideways beyond the edge of the screen,

• phone numbers can be tapped and forms are easy to fill in on a phone,

• all important content is also available in the mobile version.

3. Security: the padlock in the address bar

If your address begins with https:// and the browser shows a padlock icon, data is transmitted in encrypted form. For this, your website needs what is known as an SSL certificate. If it is missing, browsers warn visitors with “Not secure” – and that costs trust and enquiries. Google has favoured secure pages for years.

The good news: many hosting providers supply certificates free of charge, for example via Let's Encrypt. Often a single click in the customer area is enough.

4. Readability for Google and AI assistants

Even the fastest website achieves nothing if search engines are not allowed or able to read it. The most important points:

• No accidental block: The “noindex” instruction or an incorrectly configured file called robots.txt can lock Google out. How to check this is explained in Why can't Google find my website?.

• A sitemap: A table of contents of your website specifically for search engines. Most systems create it automatically – submit it in Google Search Console.

• No broken links: Pages that lead nowhere (error message “404”) annoy visitors. If a page is moved, a permanent redirect (technical term: 301) should send visitors and Google to the new address.

• Don't block AI crawlers unintentionally: Some hosting and security services block the programs of AI providers by default. Then ChatGPT, Claude & co. cannot read your content. Whether you want that is something you should decide consciously. More on this in What is GEO?.

• Important content as real text: Content that is only created in the browser through complex programming is harder for many AI crawlers to capture. Important information should be directly in the page text.

The 10-minute self-test

Conclusion: foundation first, then the façade

Technical SEO isn't glamorous, but it is crucial. A fast, mobile-friendly and secure website that search engines and AI assistants can read without problems is the prerequisite for everything else. Whether you run a bakery or a medium-sized company, a regular technical check prevents good content from failing because of a sticking door.