Link Building: Earn Backlinks Safely and Spot the Risks

What is link building?

Link building covers every measure that helps a website gain links from other websites. These incoming links are called backlinks. A backlink appears, for example, when a trade magazine points to your guide in one of its articles, or when an industry association links to your business in its member list.

Link building is part of off-page SEO, which means all the work that happens outside your own website. On-page SEO, by contrast, deals with the text, technology and internal links on your own pages. Both areas work together: without good content, you rarely get links that people give freely. For an overview of every part of search engine optimisation, see our article SEO for beginners.

Terms you should know

• Backlink: a link from another domain to your website.
• Internal link: a link from one page of your website to another page on the same site.
• Anchor text: the visible, clickable text of a link.
• Link profile: all the links pointing to your website, along with their sources and anchor texts.
• Referring domain: a website that links to you at least once. Ten links from the same domain count as one referring domain.

Why do backlinks matter for SEO?

Google writes in its documentation that links are a signal for determining how relevant pages are. Google's crawler also finds new pages through links. A link from a well-known specialist site tells search engines that others consider your content useful.

Links also play a role in local search. Google names three factors for local ranking: relevance, distance and prominence. According to Google, prominence includes links and reviews, among other things. You can read more about local search in our article on the Google Business Profile.

Google does not disclose how much weight individual links carry. Links are one factor among many, and content, technology and search intent count just as much. If you only collect links and neglect your own site, you waste their effect.

Quality over quantity

Backlinks differ in value. Whether a link helps depends on several points:

• Topical relevance: a link from a site in your own industry fits the topic of your page.
• Trust in the source: sites with real readers, their own editorial team and a clear legal notice carry weight. Sites made up only of guest posts carry little.
• Placement: a link within the body text of an article carries more meaning than one in a long footer list.
• Real value: if readers click the link, it brings you visitors, whatever its effect on rankings.

Many SEO tools show their own metrics for the strength of a domain. The providers calculate these values themselves, and they have nothing to do with Google's own assessment. In its guide to generative AI features in Search, Google states that no third-party tool has access to Google's internal ranking systems.

What does Google consider link spam?

In its spam policies, Google defines link spam as links created mainly to manipulate rankings in Search. The policy lists many examples. Here are the most important ones:

• Buying or selling links to influence rankings. This covers money for links or for posts containing links, goods or services in exchange for links, and free products in return for a review with a link.
• Excessive link exchanges along the lines of "link to me and I'll link to you", as well as partner pages that exist only for cross-linking.
• Automated programs or services that create links to your website.
• Links required by terms of service or contracts, where the linked party may not label the link.
• Paid articles, guest posts or press releases with links that pass ranking value, or with anchor text stuffed with keywords.
• Links from low-quality directories or bookmark sites.
• Hidden or keyword-heavy links in widgets distributed across many sites.
• Widely spread links in the footers or templates of many other websites.
• Forum posts or signatures with optimised links.

According to Google, a website that breaches these policies may rank lower or disappear from the results entirely. Google relies on automated systems for this and, where needed, on people who review sites. Such a manual action is reported by Google in the "Manual actions" report in Search Console.

Labelled links: nofollow, sponsored and ugc

Paid links are not forbidden as such. Google writes that buying and selling links is a normal part of the web's advertising economy. They do not breach the policies if they are labelled with rel="nofollow" or rel="sponsored". These attributes sit in the HTML code of the link. Google distinguishes three values:

• rel="sponsored": for ads and paid placements. Google prefers this value for paid links, although nofollow is still allowed for them.
• rel="ugc": for links in user-generated content such as comments and forum posts.
• rel="nofollow": for cases where the other values do not fit and you do not want to associate your website with the linked page.

You can combine several values, for example rel="ugc nofollow". Google generally does not follow links with these attributes. For your own website, this means two things. First, label links for which you receive money or something in return. Second, according to Google, nofollow is meant for cases where no other value fits and you do not want to connect your page with the target. You do not need it for every external link. Linking to your sources builds trust with readers.

Building backlinks: the right ways

A good link building strategy starts with one question: why would anyone link to you of their own accord? The following methods work without breaking any rules. They take time, and the links they deliver comply with the policies.

Content people like to link to

The most solid foundation is content with real value. Think of detailed guides, checklists, calculators, templates or explanations of questions that come up often in your industry. Specialist authors, forums and customers link to pages like these because they help their own readers. Our article on content marketing strategy shows how to find and plan topics for this.

Your own data and studies

Journalists and bloggers look for figures they can quote. If you have your own data, for example from a customer survey, from analysing your orders or from a small test, present it in a way that is easy to understand. Describe openly how you collected the data and how large the sample was. Editors can only use a figure if they can trace where it comes from. Charts and infographics make it easier for others to reuse your results and name you as the source.

Press work

Real news from your company interests local newspapers, trade media and industry portals. That might be an opening, a project with a school, an award or an expert view on a current topic. Offer yourself to editorial teams as a contact for your field. Make sure your press releases inform readers and contain no keyword-stuffed anchor texts. Google names exactly this as an example of link spam.

Industry directories and associations

A directory listing can make sense if people actually search there. Examples include the member list of your chamber or trade association, directories for your city or region and recognised industry portals. These listings help customers find you. Mass submissions to hundreds of directories without readers usually achieve nothing. Google explicitly lists links from low-quality directories as link spam.

Partnerships and collaborations

Suppliers, retailers, customers and business partners often have a page listing references or partners. A link from there is natural if the cooperation is real. The same applies to sponsoring a local club, giving talks at events or running joint projects with universities. Watch the limit: Google treats large-scale link exchanges and partner pages that exist only for cross-linking as spam. If money changed hands for a link, it needs a label.

Replacing broken links

Many websites contain links to pages that no longer exist. If you find such a broken link on a specialist site, pointing to a topic you cover well, you can let the site owner know in a friendly way. Offer your matching page as a replacement. The owner benefits because they can fix an error. Your page must genuinely be a good replacement for the old content. Keep your message short and personal, without a mass mailing.

Turning unlinked mentions into links

Sometimes other sites mention your company name without linking to you. In such cases, politely ask whether a link to your website would be possible. Readers find it handy, because it takes them straight to you.

Spotting risky offers

If you run a website, you regularly receive emails offering backlinks. In its guide to SEO service providers, Google advises caution with companies that contact you out of the blue. The following signs should make you suspicious:

• Packages by quantity: "100 backlinks for a fixed price" points to automatically generated or low-quality links.
• Promises of top rankings: Google writes that nobody can secure a first place for you.
• "Dofollow" only: anyone who explicitly promises unlabelled, paid links is offering exactly what Google classifies as link spam.
• Link networks: many websites from the same provider, without real readers, linking to each other and to clients.
• Unclear sources: the provider does not tell you in advance on which websites the links will appear.
• Exact-match keyword anchors: the provider wants to use your target search term as the anchor text for every link.

According to Google, link schemes and mass submissions are mostly useless. In the worst case, you put your visibility at risk. Even if an agency buys the links on your behalf, you as the site owner bear the consequences.

What does a link building agency do?

A link building agency is a service provider that specialises in building backlinks. Link building is also often part of what an SEO or online marketing agency offers. Typical tasks include:

• analysing the existing link profile and comparing it with competitors,
• planning or creating content that is worth linking to,
• researching and contacting suitable media, blogs and partners,
• press work and topic suggestions for editorial teams,
• finding broken links and unlinked mentions,
• reporting regularly on which new links have been added.

What to look for when choosing one

Ask how the agency obtains links and on which websites they appear. A reputable agency explains its methods openly and follows Google's spam policies. Ask to see examples, ideally the linking pages themselves. Clarify whether links are paid for and, if so, whether they are labelled. Stay involved in the strategy. Google points out that the responsibility remains yours, even when a service provider does the work. You will find more questions for a first meeting in our article What does an SEO agency do?

Checking backlinks: the Links report in Search Console

Google shows you for free in Search Console which websites link to you. The Links report contains several tables:

• Top linked pages: which of your pages receive the most backlinks. One click shows the websites linking to that page.
• Top linking sites: the domains that link to you most often.
• Top linking text: the anchor texts of external links. Links without text, such as image links, appear as "(empty)".
• Internal links: which pages within your website are linked most often.

According to Google, the report shows a sample, not a complete list. Tables are limited to 1,000 rows. The report also includes links that Google found in the past and that may no longer exist. It does not show whether a link is marked nofollow. With the export function, you can download up to 100,000 rows as a table, either the latest links found or a larger sample.

How to analyse the report

• Check the list of linking sites for unknown domains. Google advises taking a closer look at suspicious sites.
• Read the link texts. According to Google, they should match your expectations and contain no spam text.
• See which of your pages attract links. Often it is the home page and a few guides. This tells you which content others find interesting.
• Use the internal links table. Important pages should also be well linked within your own website.

Removing or disavowing spam links

Google states that it generally ignores links from known spam sites. For most websites, there is therefore nothing to do. If you bought links in the past, or a service provider did so for you, first try to have those links removed at the source. Google describes the disavow tool, which lets you ask Google not to take certain links into account, as an advanced feature that carries risk. According to Google, it only makes sense if many artificial links point to your site and they have triggered a manual action or are likely to. Used wrongly, it can harm your visibility.

Summary

Backlinks remain a signal Google uses to assess how relevant pages are. Bought or exchanged links without a label breach the spam policies. Links that hold up come from content with real value, your own data, press work, memberships and genuine partnerships. Check your link profile regularly in the Links report in Search Console. You will find more of the basics on our topic page SEO.

Sources: Google Search Central, "Spam policies for Google web search" (as of 28.08.2026); "Qualify your outbound links to Google" (as of 10.12.2025); "Make your links crawlable" (as of 10.12.2025); "Do you need an SEO?"; "Optimizing your website for generative AI features on Google Search" (as of 10.07.2026); Search Console Help, "Links report" and "Disavow links to your site"; Google Business Profile Help, "Tips to improve your local ranking on Google".