Backlinks are hyperlinks from one website to another. They serve as indicators of a website's relevance and trustworthiness in the eyes of search engines. The more backlinks you receive from authoritative, high-quality websites, the better your chances of ranking well in search results.

A basic backlink looks like this in HTML:

<a href="https://my-company.com">My Company</a>

A backlink — also commonly referred to as an inbound link or incoming link — is a hyperlink from an external website that points to your website.

In SEO, backlinks are one of the most important ranking signals because they act as a vote of trust and authority from one website to another.

Google and other search engines evaluate backlinks as indicators of relevance, authority, and content quality. In addition to their SEO value, backlinks also help users navigate between websites and generate referral traffic independently of search rankings.

High-quality backlinks can significantly improve a website's position in search engine results, making backlink building an essential part of any serious SEO strategy. If you are just starting out, our guide on how to build backlinks for a new website is the best place to begin.

Backlinks function as digital endorsements. When another website links to yours, it signals to search engines that your content is valuable, credible, and worth referencing.

Websites with a larger number of high-quality backlinks consistently rank higher in search results. This is why link building remains a central pillar of off-page SEO, even as search engine algorithms become more advanced. For a deeper look at whether this is still true today, read our analysis of whether backlinks still matter in 2026.

Backlinks do more than improve rankings. They also:

  • Increase the credibility and trustworthiness of your website
  • Drive direct referral traffic from external websites
  • Expand your online reach and audience visibility
  • Help search engines discover and index new pages faster

Not all backlinks are equal. Quality is the single most important factor when evaluating the value of a backlink.

A high-quality backlink typically comes from a trustworthy, authoritative, and topically relevant website.

Several SEO tools use proprietary authority metrics to estimate the strength of a domain:

  • DR (Domain Rating) — developed by Ahrefs, measured on a scale from 0 to 100
  • DA (Domain Authority) — developed by Moz, measured on a scale from 0 to 100

A single backlink from a reputable and relevant website is typically more valuable than dozens of low-quality links from unrelated sources.

Topical relevance also plays a major role. For example, a recipe blog benefits most from backlinks coming from food-related websites. A backlink from a completely unrelated niche may carry less SEO value, even if the linking domain itself is authoritative.

The ideal backlink combines:

  • High domain authority
  • Strong topical relevance
  • Real organic search traffic

Backlink quality alone is not enough. The structure and diversity of your overall backlink profile are equally important.

DoFollow vs. NoFollow Balance

A natural backlink profile includes both DoFollow and NoFollow links. Understanding the difference between NoFollow and DoFollow backlinks is essential for building a healthy profile.

  • DoFollow links pass authority and directly influence search rankings.
  • NoFollow links do not traditionally pass ranking authority but still contribute to a natural link profile and can drive referral traffic.

Anchor Text Diversity

Anchor text is the clickable text used within a hyperlink. A healthy backlink profile includes varied anchor text types, such as:

  • Branded anchors
  • Generic anchors
  • URL anchors
  • Occasional keyword-rich anchors

Repeating the exact same keyword-rich anchor excessively can appear manipulative and may trigger search engine penalties.

Domain Diversity

Links from many unique domains are generally more valuable than many links from a single website.

For example, one hundred backlinks from one hundred different websites usually provide more SEO value than one hundred links from a single domain.

A natural backlink profile signals organic popularity and trustworthiness to search engines.

Monitoring your backlink profile regularly is crucial for maintaining healthy SEO performance.

Regular backlink analysis helps you:

Tools such as Ahrefs, Semrush, and Google Search Console make backlink auditing and monitoring significantly easier. For a full comparison of the best free options, see our guide to the best free backlink checker tools in 2026.

Organic backlinks occur naturally when other websites choose to link to your content because they genuinely find it useful, informative, or valuable.

These backlinks are considered the most valuable by search engines because they represent authentic editorial recommendations.

Building organic backlinks consistently requires publishing high-quality, unique, and genuinely helpful content that others naturally want to reference. Our guide covering 12 proven strategies to get backlinks covers the most effective methods in detail.

Paid backlinks carry significant risks. Many websites and networks exist solely to sell links, and search engines actively work to detect and devalue these practices. For a full breakdown of the risks involved, read our guide on white hat vs black hat link building.

If you consider paid placements, strict quality standards are essential:

  • High domain authority
  • Real organic traffic
  • Strong topical relevance

SEO can work without backlinks in low-competition niches where strong content, technical SEO, and excellent user experience are sufficient to rank well.

However, in competitive industries, backlinks are almost always necessary to achieve and maintain high search rankings.

Backlinks build authority and trust signals that on-page optimization alone cannot fully replace.

A successful SEO strategy therefore treats backlinks as a long-term investment and an essential complement to strong on-page SEO. If you are wondering where to start, our guide to getting backlinks without spending money covers ten proven free strategies.

Not all backlinks are beneficial. Links from spammy, irrelevant, or penalized websites can negatively affect your rankings. Learn more about how to identify them in our guide to toxic backlinks and how they hurt your SEO.

If you identify toxic backlinks, the recommended process is:

  1. Contact the webmaster of the linking website and request removal of the backlink.
  2. If removal is not possible, use Google's Disavow Tool in Google Search Console to ask Google to ignore specific backlinks. Read our full walkthrough on how to use Google's Disavow Tool correctly before taking action.

The Disavow Tool should be used carefully. Incorrectly disavowing legitimate backlinks can negatively impact your website's SEO performance.

Any disavow decisions should be based on a thorough backlink audit and solid SEO expertise.