An external link is a hyperlink on a webpage that points to a page on a different domain, sending the user away from the originating site. Also called an outbound link, it is the counterpart to an internal link, which connects pages within the same domain. In SEO, external links carry significant meaning because they signal to search engines how a page relates to the broader web of information.
How External Links Affect SEO
Search engines like Google interpret external links as editorial endorsements of context and relevance. When a page links out to a well-regarded source, it provides a signal that the content is grounded in credible, verifiable information. This is not about passing authority away from your site, but about demonstrating that your content exists within a trustworthy ecosystem. Linking to authoritative sources, such as academic publications, government websites, or established industry references, can reinforce the topical depth of a page and support its perceived expertise.
It is worth distinguishing an external link from a backlink. A backlink is an inbound link, meaning another domain is linking to your site. An external link is the outbound perspective of the same relationship. Both matter in SEO, but they serve different functions: backlinks build a site's authority, while external links contribute to its relevance and trustworthiness.
Link Attributes and Crawl Behavior
Not all external links pass the same signals to search engines. A standard external link without any special attribute is treated as a followed link, meaning search engine crawlers will follow it and may factor it into their understanding of your page. Adding a rel="nofollow" attribute instructs crawlers not to follow the link or associate it with your endorsement. Variants such as rel="sponsored" and rel="ugc" (user-generated content) exist to flag paid links and community contributions respectively, helping search engines understand the nature of the relationship.
Outbound Linking Considerations
Thoughtful outbound linking is a signal of editorial quality. Linking to low-quality, spammy, or irrelevant domains can reflect poorly on a page's credibility, while linking to authoritative, topically relevant sources supports it. The anchor text used for external links also matters: descriptive, relevant anchor text helps both users and search engines understand what the linked page covers before visiting it.
Opening external links in a new tab is a common usability choice, though it has no direct SEO impact. More consequential is ensuring that outbound links are not broken, since dead links diminish user experience and suggest a page is poorly maintained. Regularly auditing external links as part of a broader site health routine helps preserve both usability and the quality signals a page sends to search engines.