Technical SEO in 2025

Table of contents:

• Introduction to technical SEO
• What is technical SEO?
• Why Technical SEO?
• 6 Important technical SEO points
• Technical SEO trends in 2025
• Technical SEO optimisation by specialists
• The free SEO technical checklist
• Blogs about technical SEO
• Frequently asked questions about SEO

Introduction to technical SEO

Want more relevant visitors to your website? Then good findability in Google is indispensable. The higher you are in the search results, the greater the chance of new customers.

Good SEO copy is important for this, but technical SEO is just as important. Think of a clear structure, correct 301-redirects and a fast loading time. Such improvements make your site easier to find and more user-friendly.

Technical SEO also makes your site more secure and easily accessible on mobile devices.

In short: improve your technology, and increase your online visibility as well as your visitors' experience.

What is technical SEO?

With technical SEO, you make sure your website ranks better in Google. By applying the right technique, your pages will be found faster and your site will get a higher search engine rating.

This is how you climb up the search results step by step.

Technical tools help you make your website more scannable for Google. The better the technical SEO, the more valuable Google rates your site - and the faster your ideal customer finds you.

Examples of technical SEO are:

• A user-friendly structure
• Faster page load times
• Detecting and resolving duplicate content
• Showing the right page - even if something goes wrong
• Getting smart with your crawl budget

Help me with technical SEO

Why technical SEO?

Search engines like Google use crawlers to assess your website. These crawlers, although powered by sophisticated algorithms, are essentially quite simple. Therefore, it is important to guide them properly on your website to optimise its findability.

When optimising your website usability a big role. Does a webshop load slowly? Then visitors drop out quickly. Do they have to click too much to find a product? Then they prefer to look further.

But this is also important for Google. This is because the search engine not only looks at your SEO texts, but also at the technical backend of your site. Think about:

• Do all the links work?
• Do your pages load quickly?
• Does duplicate content occur?
• Is the navigation clear?

This is how Google looks at your site

Before your website is visible in search results, Google has to index it. To do this, it uses crawlers: bots that view and evaluate your pages one by one. By technically optimising your website SEO, you help these crawlers understand your site faster and better. The result? A higher ranking in the SERP.

It works the other way around too: if your technique is not right, Google won't understand your site as well. And that can limit your visibility considerably.

Technical SEO check

6 Important technical SEO points

Time to get into the technical SEO dive in. Also zonder technical background, you can start using it on your own website today.

We show you:

• what exactly crawling and indexing is
• how to get better visibility in Google
• and how to make your website user-friendly for search engines and visitors

Still prefer to leave the work to the experts? Then take contact with us! Or request the FREE SEO scan to!

1. Crawling and indexing

It all starts with crawling and indexing.

Before your pages are visible in Google, Google's crawlers must first be able to find them. Those crawlers (a kind of digital spider) follow links on the web to jump from page to page.

But: they cannot go on indefinitely. Google sets a limit: the crawl budget. That's the number of pages the crawler visits on your site within a given time. With good technical optimisation, you can speed up that process. That way, you get more out of that crawl budget, and let Google discover more pages in less time.

XML sitemaps: the map for crawlers

A XML sitemap is an overview of all the important pages on your website. Think of it as a blueprint that you send along to Google.

In it, you indicate which pages have priority. That way, you help crawlers find and index the right content faster.

Different types of sitemaps
Besides the general sitemap, there are three variants, each of which has its own function:

• Video sitemap: helps Google better recognise and understand videos on your site
• Image sitemap: gives search engines insight into all the images on your website
• Google News sitemap: ensures that Google quickly picks up content relevant to Google News

You can easily submit these sitemaps via Google Search Console. Within days, these tools collect data and give you insight into which pages are or are not being indexed.

Control what Google can and cannot see
Do you want Google to be able to index your content? Then you need to make sure you don't accidentally block it.
There are three main tags that determine which pages may or may not be indexed:

• robots.txt - with this, you exclude certain pages or folders from crawling. Googlebot won't get there then.
• noindex tag - causes a page not to appear in search results, even if it is reachable.
• nofollow tag - indicates that Google does not need to track or crawl a specific link.

Use these tags deliberately. They give you control over what Google may or may not show....

2. Structure and navigation

A clear structure helps visitors find what they are looking for quickly. But it is also important for Google. The better the structure, the easier search engines can index your website.

Make navigation easy for man and machine: Provide a clear layout where users can easily find their way around. This not only helps your visitor, but also makes technical SEO easier.

Keep your hierarchy flat: Try to keep a flat website structure. That means: each page is accessible with just a few clicks. The better you do this, the less likely you are to have so-called 'orphan pages'. These are pages zonder internal links, which is why Google often does not find them and does not include them in search results.

3. Internal link structure

Make sure your web pages are onderling linked. Are you writing a new blog? Then add links to relevant, previously written articles as you write it. For example, as we do hereonder with a link to our blog on internal link structure.

Keep your URL structure logical and clear
The bigger your website, the more important a good URL structure is. Put new products onder a clear category. It works the same way for content: bundle articles onder themes.

Use breadcrumbs for clear navigation
Breadcrumbs help visitors find their way back to your site. Like Hansel & Gretel, they leave a trail behind. You often see them at the top of the page, for example in webshops.
Say you are looking at a product page of a macbook, the breadcrumbs might be structured like this:
Home > laptops > Apple > macbooks

Not only useful for Google, but also for your visitors!

Help me with technical SEO

4. Duplicate content

Unique content is the engine of your website. It attracts visitors, retains them longer and increases your visibility in Google. As soon as the same texts or pages recur in multiple places, it creates duplicate content.

Duplicate content can arise in a number of ways. Think of landing pages that use largely the same text, or product pages that you copy for variants with minimal differences. Technical choices also come into play, such as showing the same page through multiple URLs.

An online shop is particularly sensitive to this. Suppose you offer product filters: the text on the category page remains the same, while only the product overview changes (e.g. based on size, colour or material). To Google, these appear to be very similar pages.

What can you do about duplicate content?

canonical tag to indicate which version of a page is preferred by search engines. Want to exclude a page from the index altogether? Then use a noindex tag. And with the robots.txt file you can actually block search engines from accessing certain pages. This way, you keep control over which content is or is not indexed and prevent duplicate content from hurting your SEO performance.

5. Avoid 404 pages

A 404 page appears when a visitor opens a URL that no longer exists. This often causes frustration for your visitors and can worsen your findability in Google.

You avoid 404 errors by:

• Forward deleted pages with a 301 redirect to a relevant new page.
• Updating changed URLs in internal links so that visitors and search engines do not hit a dead end.
• Regularly check your website with tools such as Google Search Console or Screaming Frog to identify error messages in time.
• Always use logical URLs, so you are less likely to encounter problems in future adjustments.

By actively avoiding 404 pages, you offer visitors a better experience and preserve your website's accumulated SEO value.

6. Website migrations

With a website migration, you run an extra risk of SEO loss and 404 errors. If you change the structure, URLs or technology of your site, it is important to carefully redirect old pages with 301 redirects. This will keep your visitors and search engines on track to the right content. Make a migration plan in advance in which you map all current URLs, set up a redirect mapping and, after going live, check via Google Search Console whether everything is handled properly. A well-prepared migration avoids losing accrued value and ensures a smooth transition.

There are several reasons why a SEO migration takes place:

• Merging content
• A change of URLs
• A switch from a hosting provider
• A redesign of the website
• Merging two entire websites
• A change of domain name
• A change in the structure in the URLs
• A change from http to https
• A new CMS

See all the technical points?
Then download our technical seo checklist!

Technical SEO optimisation at onder

Our technical seo analysis covers everything your web builder may have overlooked. While the foundation for a high-scoring website is laid at the time of construction, web builders don't always pay attention to SEO techniques. We therefore look at the technical aspects of your website and assess whether they meet the standards of technical SEO.

A common technical problem we encounter is the speed of a website, which is why this is a major focus of our technical SEO analysis. Moreover, nowadays a website needs to function properly on different mobile devices, we include this too.

Working method of our technical SEO specialists

The technical SEO specialists always include several key points in our technical SEO check:

• Page crawlability: can all relevant pages be found by the crawlers? For this, you onder other need a good sitemap, a solid link structure and the robots.txt file must be in order. We also check redirects and possible 404 errors.
• Content indexability: we check whether your website content is optimally 'readable' by crawlbots.

• Structured data: this is a way of labelling certain content for bots. For example, a phone number, which without structured data is just a string of numbers for a crawlbot.
• OpenGraph and images: We check whether your website properly uses Open Graph tags to optimise content sharing on social media. We also analyse the optimisation of images on your site, including their size, alt-texts and whether they appear correctly in the sitemap.

After going through these and more points, you will receive a detailed technical SEO checklist. We also point out the points with the greatest potential, so you know where to start, but of course we can do the work for you too!

Technical SEO trends in 2025

1. Get more out of your crawl budget
Large websites more often run into a limited crawl budget. Don't waste that precious crawl time on unimportant pages. Use your robots.txt to exclude unnecessary pages, remove outdated internal links and work with a clear sitemap. That way, you let Google focus on your most important content and new pages are indexed faster.

2. Stand out with structured data
Rich snippets and AI views make structured data more important than ever. With good schema markup, Google better understands what is on your page. This increases your chances of getting extra visibility through FAQs, reviews or product information in search results.

3. Score better with Core Web Vitals 2.0
Google continues to reward user experience. In 2025, it's all about Interaction to Next Paint (INP): how quickly does your website respond to user actions? Ensure fast, smooth interaction. This has a direct impact on your rankings.

4. Keep JavaScript SEO-proof
Are you using frameworks such as React or Vue? Then it is important to think about server-side rendering or dynamic rendering. Google can read JavaScript, but does not always do so properly or quickly. With the right technology, you make sure all your pages are indexed properly.

5. Close international SEO
Do you work with multiple languages or countries? Then make sure you have a good technical base. Hreflang tags are essential to show the correct version of your page in each country. A mistake could mean Google shows the wrong language and that will cost you visitors.

Technical SEO checklist

Frequently asked questions about technical SEO

What is technical SEO?
Technical SEO includes all the optimisations that ensure search engines like Google can easily crawl and index your website. It includes onder other aspects like website speed, mobile usability, XML sitemaps, and structured data.

Why is loading speed important for SEO?
A fast website provides a better user experience and prevents visitors from dropping out. In addition, Google uses loading speed as a ranking factor. Optimisations such as image resizing, caching and limiting scripts contribute to this.

What is the difference between an XML sitemap and a robots.txt file?
An XML sitemap gives search engines an overview of all the important pages on your site so they can index them faster. The robots.txt file is used precisely to prevent search engines from crawling certain pages or directories.

How to avoid duplicate content with technical SEO?
Duplicate content is often solved with canonical tags or 301 redirects. These indicate which version of a page is the main version. This way, you bundle the SEO value and prevent Google from seeing multiple pages as duplicates.

What is a hreflang tag and when do you use it?
An hreflang tag tells Google which language and country version of a page is intended for a specific target audience. This is important for international websites, so that the correct variant appears in search results.

Blogs on discussed technical SEO onderwerpen:

• The ins and outs of a good internal link structure.
• Sitemaps explained and 3 tips
• What types of crawlers are there?
• What is duplicate content and how do you check it?
• What is a canonical tag and how do you use it?
• Using robots.txt optimally
• What is a 404 and how do you solve it?
• What is a 301 redirect and how do you create one?