External Links

## Why it matters

Outbound links to relevant, credible sources signal a well-researched page. Google treats links to authoritative sources as a trust signal. High volume of links to low-quality or unrelated domains (a classic footer link-farm pattern) is a spam signal under Google's policies.

The rel attribute on each external link also discloses paid or user-generated links. This is a compliance requirement, not optional. Sites caught running unmarked paid links risk manual actions from Google's spam team.

## How it works

An external link is any <a> tag whose href resolves to a different registrable domain than the page itself. The classification process is straightforward:

1. Parse the page's <a> elements with href attributes.
2. Extract the destination domain from each href.
3. Compare it to the page's own domain (registrable domain, not hostname; www.example.com and example.com are the same domain).
4. If different, it's external. If the same, it's internal.
5. Then examine the rel attribute to sub-classify: plain (no rel), nofollow, sponsored, ugc, or combinations.

The distinction that matters is registrable domain. www.example.com, example.com, api.example.com, and blog.example.com are all the same registrable domain, so a link from one to another is internal, not external. A link to example.com from a page on someoneelse.com is external.

## What does not matter

Outbound link volume alone is not a ranking factor. A page with 100 external links can rank well if those links go to high-quality, relevant destinations and are disclosed correctly via rel attributes. A page with 5 external links to spam domains and no rel disclosures is a red flag.

Google's treatment of the rel attribute has evolved. A nofollow link does not guarantee zero crawl or zero ranking value; Google treats nofollow as a hint, not a directive, and may crawl nofollowed links if it judges them useful. The compliance risk is in running paid links without any disclosure at all.

## Code example

Here's how to audit a page's external links and check for missing rel attributes:

// Audit external links and their rel attributes
const auditExternalLinks = () => {
  const currentDomain = new URL(window.location.href).hostname;
  const externalLinks = [];

  document.querySelectorAll('a[href]').forEach(link => {
    const href = link.getAttribute('href');
    const rel = link.getAttribute('rel') || 'none';
    
    try {
      const url = new URL(href, window.location.href);
      
      // Check if external
      if (url.hostname !== currentDomain) {
        externalLinks.push({
          url: url.href,
          anchorText: link.textContent.trim(),
          rel: rel || 'no rel attribute',
          hasNofollow: rel.includes('nofollow'),
          hasSponsored: rel.includes('sponsored'),
          hasUgc: rel.includes('ugc')
        });
      }
    } catch (e) {
      // Skip malformed URLs
    }
  });

  // Flag missing rel attributes on external links
  const missingRel = externalLinks.filter(l => l.rel === 'none' || l.rel === 'no rel attribute');
  console.log(`External links: ${externalLinks.length}`);
  console.log(`Links with no rel attribute: ${missingRel.length}`);
  console.table(missingRel);
};

auditExternalLinks();
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This script walks every external link and reports which ones are missing a rel attribute. Audit the results: are paid links (ads, affiliates, sponsorships) marked rel="sponsored"? Are user-generated links (comments, reviews) marked rel="ugc"? Missing disclosures are a compliance risk.

## How Scalpel shows it

The Links tab displays all external links found on the page, grouped by their rel attributes (plain, nofollow, sponsored, ugc). For each link, it shows the destination domain, anchor text, and rel value. Scalpel flags broken external links (404, timeout, or unreachable) and highlights low-quality destinations (known spam or malware domains). The extension also warns if external links to competitors or adjacent industries outnumber links to neutral resources or sources.