Technical SEO

Technology is the technical foundation of your website. The prerequisite for successful SEO work is that there are no technical errors or inadequacies on the website that reduce the quality of the website and prevent Google from indexing all or part of the website.


What is technical SEO?

Technical SEO (also called platform optimization) is the optimisation of the technical platform behind your website. The prerequisite for successful work with SEO is that there are no technical bugs or inadequacies on your platform that degrade the quality of the website and prevent Google from indexing all or part of the website.

Many companies invest large sums in developing a beautiful and user-friendly website. But many - including the web agencies that develop the website - forget to consider SEO in the development. That's a problem, because Google doesn't understand your slick design, and your expensive website is essentially worthless if your target audience can't find it on Google.

The following review of SEO technical areas can be used as a requirements specification when developing a new website and as a checklist when optimising an existing website. It's a complex area, and if you make a mistake in the process, you risk bringing down your entire website in a split second. That's why it's important that you or your web developers have complete control over what you're doing.

The areas outlined below are basic principles that apply to any website - regardless of which CMS system it is built in (WordPress, TYPO3, Umbraco, Joomla, Drupal, Magento, Shopify etc.). Some CMS systems require more attention and more work than others, but it would be too extensive here to go into detail about each system.

Areas of technical SEO

  1. Sitemap
    A sitemap is an overview of all pages and content on a website. It is primarily designed for use by search engines so that they can better index and understand the content on the website. A sitemap can either be a simple text file that contains a list of URLs on the website, or it can be an XML file that provides search engines with more detailed information about each content element on the website.A sitemap xml file is a specific type of sitemap that is written in XML format. This allows more detailed information to be provided about each page on the website, such as the page title, update frequency and priority relative to other pages. This can help search engines understand which pages are most important on the website and how they should be indexed. A sitemap xml file can also contain other information such as the language of the page and the last modification date of the page.You can click on the link here to see Google's recommendations for an XML sitemap
  2. Robots.txt
    Robots.txt is a file that resides on a web server and contains instructions to search engines and other crawlers about which pages on the website can or cannot be visited. The file is used to tell search engines which parts of the website to ignore when they scan the website to index its content. This can be useful to protect sensitive pages on the website or to avoid search engines wasting time indexing pages that are not relevant to users.
    See Google introduction to Rotots.txt
  3. Speed optimization
    Speed optimisation is about making a website as fast as possible. This is important because users expect a website to load quickly, and a slow load can lead to users leaving the site again. Therefore, speed optimisation can help improve the user experience and increase traffic to the website.There are several different methods of speed optimisation. One method is to minimise the size of images and other content on the website so that it loads faster. Another method is to use caching, which allows a copy of the website to be stored in the browser so that it does not have to be loaded from the server each time the user visits the website. A third method is to optimise the code of the website so that it loads faster. This can be done by removing unnecessary code and structuring the code in a way that makes it easier for the browser to interpret. Speed optimisation can be a time-consuming process, but it can help increase both the user experience and the conversion rate of the website.Read more about speed optimisation on our blog here:
  4. Mobile friendliness
    Mobile-friendliness is an important aspect of modern web design, as it ensures that your website can be used and displayed correctly on a wide range of mobile devices, including smartphones and tablets. This is vital as an increasing proportion of internet users are using mobile devices to browse the web, and a mobile-friendly website will significantly increase your potential audience.A mobile-friendly website will also improve the user experience for your visitors. A website that is not mobile-friendly can be difficult to navigate and read on a mobile device, which can result in frustrated visitors who leave the site quickly. A mobile-friendly website, on the other hand, will be easy to use and read, which can encourage visitors to stay longer on the site and possibly lead to more conversions. Another reason to have a mobile-friendly website is that it can improve your search engine optimization. Some search engines, including Google, take into account whether a website is mobile-friendly when determining its ranking in search results. This means that a mobile-friendly website can rank higher in search results, which can increase traffic to your website. All in all, mobile-friendliness is a crucial aspect of modern web design, and it's an investment that can pay off in terms of increased visitor traffic, improved user experience and better search engine optimisation.
  5. AMP (Accelerated Mobile Pages)
    AMP (Accelerated Mobile Pages) is a technology that enables web pages to load faster on mobile devices. This is an important feature as fast loading of a website can significantly improve the user experience, especially on mobile devices where internet connections are often slower than on desktop computers. Another benefit of using AMP on your website is that it can improve your search engine optimisation. Some search engines, including Google, will give a higher ranking in search results to web pages that use AMP, as this signals that the page is fast to load. This can result in more visitors to your website and greater visibility in search results. Using AMP can also help improve the user experience on your website. AMP pages are designed to be simple and easy to navigate, which can make it easier for your visitors to find what they are looking for on your website. This can encourage them to stay longer on the page and possibly lead to more conversions.
    Overall, AMP is a useful technology for modern websites, as it can improve load time, user experience and search engine optimisation. It is an investment that can pay off in terms of increased traffic and conversions.
  6. Domain
    A domain name is a unique name assigned to a website and used to identify it on the Internet. It plays an important role in search engine optimisation (SEO) as it can affect how a website ranks in search results. A strong domain name can help improve a website's ranking in search results as it can give an indication of what the site is about. Search engines often use the domain name as a factor when deciding which pages to rank higher. It is also a good idea to choose a short and easy to remember domain name, as this can make it easier for people to find the site using a search engine or by typing the name directly into their web browser. In general, it is a good idea to take the time and effort to choose the right domain name, as it can have a big impact on a website's SEO success.
  7. Subdomains and subfolders
    And subdomain is a standalone domain that is linked to your main domain. The subdomain is specified in front of the main domain, separated by a period, so a web address with a subdomain has the following format: subdomain.domain.uk. The text www in most domain names (www.domæne.dk) is actually a subdomain. Unique subdomains act as a substitute for www, and therefore it is very rare to use both www and a unique subdomain in the same domain name. A subdomain tells Google and your visitors that the content on the subdomain is separate from the content on the rest of your website. Subdomains are therefore often used to divide the content of a website into smaller and more manageable parts. For example, some people place their blog on a subdomain (blog.domain.dk).Even though the subdomain is a subdivision of your domain, Google interprets it as a website in its own right. This means that the SEO value of your main domain is transferred to your subdomain (and vice versa) to a very limited extent. When creating a subdomain, you therefore need to start SEO optimisation from scratch. Most hosting companies allow you to create an unlimited number of subdomains for free. The creation is usually done via your control panel and you will then be able to add content to the subdomain via a subdomain folder on your web server.What is a subfolder?En subfolder is a sub-section of your website that often contains related content. The subdirectory is named after the domain name, separated by a slash, and a web address with a subdirectory has the following format: domain.dk/subdirectory/.Subdirectories can be used to categorise content and to make the structural organisation of the website visible. For example, if you have different sections on your website, you can create a subdirectory for the content in each section (domain.dk/section/content), making it visible to Google and your visitors which section the content belongs to.

    Google interprets subdirectories as part of your domain, and therefore the SEO value is transferred from the main domain to all subdirectories. However, you still need to SEO optimise the content in the subdirectories because each content page is to some extent individually rated by Google.

    You can easily create an unlimited number of subfolders on your web server - it's the same as creating folders on your computer. If you use a CMS system (for example WordPress or Joomla), subfolders are usually created automatically, in such a way that the subfolders reflect the menu structure of your website.

    Read more about subdomains and subfolders here

  8. URL

    A URL (Uniform Resource Locator) is an address used to access a specific page on the Internet. For search engine optimisation (SEO), it is important to have good, descriptive URLs for your web pages. This can help search engines understand what the page is about and can therefore contribute to a higher ranking in search results.

    A good URL should be short and descriptive. It is best to include the keywords of the page in the URL so that it is easy for search engines to see what the page is about. It's also a good idea to avoid characters like hyphens and underscores, as these can make the URL difficult to read.

    It's also a good idea to make sure your URLs are unique and easy to remember. This can make it easier for users to find and share the page, and can thus contribute to higher traffic to the page.

    All in all, it's important to have good URLs to improve your ranking in search results and increase traffic to your site. By including keywords and making URLs unique and easy to remember, you can increase your site's visibility and contribute to better SEO.

  9. WWW (World Wide Web)

    Google interprets "https://www.eksempel.dk" (with WWW) and "https://eksempel.dk" (without WWW) as two different domains. In other words, if your website can be accessed both with and without WWW, you are spreading the SEO value of the website over two domains, and at the same time you risk being penalised by Google for duplicate content because the same content exists on two domains.

    Make sure your website can only be accessed either with or without WWW. You can do this by creating a 301 redirect from one version to the other. It has no SEO significance whether you choose the version with or without www, but if you have an existing domain, you should choose the version that most people link to, because that way you retain as much of the links' SEO value as possible.

    You should also take into account your target audience. If your target audience are regular internet users, they are used to typing web addresses without WWW. On the other hand, if your target audience is older and less used to the Internet, the version with www is often a more appropriate choice. Several of the largest websites such as Google, Facebook, Wikipedia and Yahoo all use WWW.

  10. HTTPS

    A secure website is one that uses the HTTPS (Hypertext Transfer Protocol Secure) protocol to ensure that data sent between the website and the user's browser is encrypted and protected from unauthorised access.

    There are several reasons why you should have a secure website. First of all, it protects your users' personal information, such as credit card numbers and passwords. Without HTTPS, this information can be intercepted by unauthorised people, which can lead to fraud and identity theft.

    Another reason to have a secure website is that it can help improve your ranking in search results. Many search engines, including Google, prioritise secure websites higher in search results, so it can be a good idea to make sure your site uses HTTPS.

    Finally, a secure website can give your users a sense of trust and security. When users see that your site is secure, they will feel more comfortable using it and sharing their personal information.

    All in all, there are many good reasons to have a secure website. It protects your users' personal information, can help you rank higher in search results, and gives your users a sense of trust and security. So if you don't yet have a secure website, it might be a good idea to consider upgrading it.

  11. Redirects
    Redirects are a technique used to redirect a user from one web page to another. This can be useful in many different contexts, but it is particularly beneficial for search engine optimisation (SEO).When a search engine crawls a web page, it will follow all the links found on the page. If there is a redirect on the page, the search engine will automatically be redirected to the new page that has been redirected to. In this way, redirects can help ensure that search engines index the correct page and that search results are correct.Redirects can also be useful in situations where you want to move a web page to a new URL. Instead of letting users get a 404 error when they try to go to the old URL, you can use a redirect to redirect them to the new page so they can still find the content they are looking for.1301 redirect: This is the most common type of redirect and is used when a page is permanently moved to a new URL. This tells search engines that the old URL is no longer valid and that they should index the new URL instead.

    2. 302 redirect: This redirect is used when a page is temporarily moved to a new URL. It tells the search engines that the old URL is still valid and that they should continue to index it.

    3. Meta refresh redirect: This redirect is used when a page needs to be redirected after a certain period of time. This can be useful if you want to redirect the user to another page after a few seconds.4. JavaScript redirect: This redirect is used when a page needs to be redirected using JavaScript. This can be useful if you want to redirect the user to another page when a specific event occurs, such as when a user clicks on a link.

  12. HTTP Status Codes (response codes)
    HTTP status codes are a way for the web server to tell a user or a search engine how their request was processed. There are many different types of HTTP status codes and they all have their own specific meaning. Some of the most common HTTP status codes are:There are many different types of HTTP status codes, including:1xx Informational: These codes indicate that the request has been received and processed.2xx Success: These codes indicate that the request was processed successfully and that the content of the page was returned to the user.3xx Redirection: These codes indicate that a redirect has been made and that the user should be redirected to another page.4xx Client Error: These codes indicate that an error occurred on the user's page, such as an invalid URL or lack of permissions.

    5xx Server Error: these codes indicate that an error occurred on the server while the request was being processed.

  13. Canonical tags
     Canonical tags are HTML tags used to tell search engines which version of a page is the primary and authoritative one. This can be useful in situations where there are several different versions of a page, for example if the page can be reached via different URLs or if there is a mobile version of the page.

    When search engines index a page with a canonical tag, they will choose to index the primary version of the page specified in the canonical tag. In this way, canonical tags can help prevent search engines indexing multiple versions of the same page, which can lead to duplication of content and poorer rankings in search results.

    Another benefit of using canonical tags is that it can help improve the user experience. If there are several versions of a page, it can be difficult for the user to know which version is the right one. Canonical tags can help clarify which page is the primary one, so that the user always has access to the most up-to-date and relevant version of the page.

    For example, pages with identical content can occur if a page can be accessed with several different web addresses (for example, with and without www), if you reuse the same content across multiple pages, if you reuse content from other websites on your website, and if the same products in your webshop are in multiple product categories.

    Sorting options on category pages (e.g. sorting by price) do not make a category page unique. Different language versions of a page are considered duplicates only if the primary content is in the same language (i.e. if only the headline and other minor text are translated, while the body text remains unchanged, Google considers the page a duplicate).

    If you don't explicitly tell Google which web address is the primary one, you risk Google indexing and displaying an inappropriate page in search results. For example, your unencrypted front page (with http://) rather than your encrypted front page (with https://). And at the same time you risk diluting the SEO value of the page over several different web addresses, which are in practice the same page.

  14. Divided content
    Divided content is content that is divided into different URLs. For example, pagination is often used on product category pages with many products and on topic pages with many different blog posts. Common to these pages is that headings and textual content are the same, while products and blog posts differ from the view on the previous page.
    Page split content can cause two problems: first, you risk Google showing a different page than the page 1 search results, and users are not presented with the latest and most relevant content. Secondly, this leads to duplicate content (identical content on several different URLs), and Google is not happy about that
  15. Hreflang (language versioning)

    Hreflang (Hyperlink with Rel="Alternate" and hreflang="x") is an HTML tag used to tell search engines which language version of a page to display in search results for a particular user. This can be useful if your page has multiple language versions, for example an English version and a German version.

    The Hreflang tag must be inserted on the primary version of the page, and it must indicate the other language versions of the page. This can be done by inserting a series of hreflang tags on the page, each with the language to be displayed in the search results.

    When a user searches for a topic on a search engine, the search engine will use the hreflang tag to select the version of the page that best matches the user's language preferences. In this way, hreflang can help ensure that the user accesses the most relevant version of the page.

    So hreflang is a useful technique that can contribute to a better user experience when there are multiple language versions of a page. So if your site has multiple language versions, it may be a good idea to consider using hreflang to ensure that users always access the most relevant version of the page.

  16. Structured data
    Structured data (also called Schema Markup) allows you to mark up content on your website (for example, prices and stock status of products) so that Google and other search engines can display the content directly in search results. Using structured data can therefore have a positive impact on your search engine optimisation (SEO) work.What is structured data? Structured data (also called Schema Markup and Schema Data) is the markup of content on your website that allows Google to display information from the website (for example, contact information, reviews, events, product information, address, images, etc.) directly in search results. Structured data can be used, for example, on product pages to display price, stock status and rating: any website can make use of some form of structured data. However, it is most relevant for e-commerce websites, companies with physical stores and websites with large amounts of media content (articles, recipes, videos, courses, etc.).Usually, structured data is implemented using Scheme.org (hence the name Schema Markup) - a joint collaboration between a number of the world's largest tech companies, including Google, Microsoft and Yahoo. Specifically, it works by inserting a piece of code around selected content on the website, indicating what the content is. For example, it might be a code that indicates that here is a phone number. developers.google.com you can see many more examples of good use of structured data and read how to implement it in practice. Google offers the option, via Google Search Console, to tag data on your website rather than using structured data. However, this is not an appropriate solution because it does not help other search engines.
  17. Breadcrumbs
    Breadcrumbs are small navigation links that help users and search engines find their way around your website. They can therefore have a positive impact both on the usability of your website and on your search engine optimisation (SEO) work.Breadcrumbs (in English breadcrumbs) are small navigational links that show users where they are on the website and how that page relates to other pages on the website. Breadcrumbs can increase the usability of your website and make it easier for Google to see the coherence and relevance of pages. In addition, breadcrumbs (if you mark them with structured data) on Google instead of the page's web address (written in green), making the search result clearer and more attractive to click on:
  18. Open Graph
    By implementing Open Graph Tags on your website, you can control how the website looks when shared on social media (Facebook, LinkedIn, etc.). Read more about Open Graph Tags here and learn how to use your tags correctly.What are Open Graph Tags?

    Open Graph is a set of standard tags you can put in the section of your pages to control how your pages are displayed when shared on social media. This is beneficial because it allows you to make your business more visible, while also making your pages more appealing to click through to. Open Graph is supported by Facebook and LinkedIn, among others.

    There is a wide range of tags you can use, depending on the type of page and content. As a minimum, a page title, a page description and an image should be provided, such as:

    A complete list of all available tags for both Facebook and LinkedIn can be found at The Open Graph Protocol. Some CMS systems can automatically insert these tags and then you can easily edit their content via the backend module of your website. For convenience, many choose to build a solution that automatically copies the page Title Tag and Meta Description to the page's Open Graph tags.

    Open Graph Tags do not have a direct impact on SEO, as they only relate to social media (and thus not Google and other search engines). Nevertheless, it is a good idea to implement Open Graph Tags on your website.


After reading about the topics in the list above, you have now learned the main technical requirements for an SEO-friendly website. Your website probably already meets several of the prerequisites, so you probably only need to implement a selection of our recommendations above.

Of course, we recommend that you follow any recommendations your website does not yet comply with. This may seem like a difficult and very demanding task, but in fact several of the recommendations are often relatively easy to implement. And we promise it's time well spent.

Technical SEO is very much a stand-alone task. However, you should revisit the recommendations in this chapter if you are relaunching your website or making significant technical changes to its structure. In addition, new technical opportunities may arise on an ongoing basis that you can take advantage of - these will be included in this guide on an ongoing basis.


Henning Madsen

CEO & Chief SEO Strategist

Se forfatter

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