An external link, also called an outbound link, is a link from one website to another website. These links direct the user from the current domain to a different external source. For example, linking from a blog post to an official source, research report, news website, product page or another referenced website is an example of external linking. External links can be used to provide users with additional information and support the credibility of the content.
External links should be handled carefully from an SEO perspective. Linking to relevant, trustworthy and useful sources can strengthen the context of a page. However, this does not mean that every external link directly improves rankings. Google evaluates links through many different signals, and using external links alone does not guarantee organic performance. Therefore, external links should be added not only for SEO purposes, but also to support the user and strengthen the content.
A common mistake in external linking is treating target="_blank" and rel="external" as interchangeable. target="_blank" makes the link open in a new tab or window. rel="external" is a semantic value indicating that the link points to a source outside the current site, but it does not make the link open in a new tab and is not required for SEO. A basic external link can be written as follows:
<a href="https://www.example.com">Example source</a>
If you want a link to open in a new tab, you can use target="_blank". However, for security reasons, this should be used together with rel="noopener". noopener prevents the newly opened page from accessing the page that opened it through window.opener. MDN states that noopener or noreferrer values are important for security when using target="_blank". A proper example is:
<a href="https://www.example.com" target="_blank" rel="noopener">Example source</a>
If an external link is placed as part of advertising, sponsorship, affiliate marketing or paid promotion, different rel values should be used. Google recommends using rel="sponsored" or rel="nofollow" for paid links. For links in areas where users can add content, such as comments, forums or communities, rel="ugc" or rel="nofollow" can be used. For links you do not trust or do not want to be associated with, nofollow may be preferred. For normal, trusted and editorial links, no additional rel attribute is required.
Relevance is important when adding external links. For example, a website writing about automotive spare parts may reasonably link to technical product information, manufacturer documentation, vehicle maintenance guides or reliable automotive sources. Linking from the same page to unrelated recipe, gambling or low-quality websites can weaken user experience and damage content trust. The purpose of an external link should be to inform the user better and strengthen the context of the content.
The number of external links should also be evaluated according to context. There is no fixed rule requiring the same number of external links on every page. What matters is that the links are natural, relevant and useful for the user. Adding too many unnecessary external links can distract users, weaken the focus of the page and create trust problems. On the other hand, not linking to any external source may mean failing to provide enough references, especially in informational, research-based, guide or news content.
External links do not replace internal links. Internal links help users reach related pages within the same website and help search engines understand site architecture. External links direct users to trustworthy and complementary sources outside the website. In a healthy SEO structure, both internal linking and external linking should be planned according to purpose. However, these two structures serve different functions and should not be treated as alternatives to each other.
Broken external links, meaning links that no longer work or lead to 404 error pages, should be checked regularly. If a user clicks a link to reach a source and encounters an error page, the experience is negatively affected. A large number of broken links can also create a weak impression of site maintenance quality. Therefore, external links should be audited periodically, and broken links should be updated, removed or replaced with more accurate sources.
The idea that “linking to a better source will reduce my site’s value” is not a correct SEO approach. Linking to useful, trustworthy and relevant sources can improve the reference quality of your content. What matters is that users can find the answer they need on your page and that external links act as complementary sources supporting that experience. Linking to valuable sources does not mean that your own content is weak.
External link performance can also be measured. Google Analytics 4, Google Tag Manager or other analytics tools can track which external links users click. This data helps understand which sources users are interested in, which content drives more outbound clicks and how links function within the page. However, when tracking external link clicks, user privacy, cookie preferences and the measurement setup should be configured correctly.
Trustworthiness should be one of the main criteria in an external linking strategy. Official institutions, academic sources, industry authorities, manufacturer pages, reliable publications and high-quality sources directly related to the topic should be preferred. Links to spammy, low-quality, misleading, harmful or deceptive websites should be avoided. For links involving advertising, collaboration or paid placement, the appropriate rel values should be used and the user experience should remain transparent.
In summary, an external link is a link from one website to a different domain. When used correctly, it provides users with additional resources, strengthens content context and creates a more trustworthy experience. However, the SEO value of external links is not automatic or guaranteed. Links should be relevant, trustworthy, natural and useful for the user. For links that open in a new tab, target="_blank" should be used together with rel="noopener" for security; for advertising, sponsored or user-generated links, attributes such as sponsored, ugc or nofollow should be applied correctly.
