Operated by Meta
This is the primary crawler for Facebook. It fetches content to generate previews (title, description, image) when a link is shared on Facebook.
This is the primary crawler for Facebook. It fetches content to generate previews (title, description, image) when a link is shared on Facebook.
facebookexternalhit is operated by Meta to generate rich link previews when URLs are shared on their platform. It sends GET requests to your URL, reads <meta property="og:..."> and <meta name="twitter:..."> tags, and caches the result. Blocking facebookexternalhit means all links to your domain shared on Meta appear as raw text without thumbnail, title, or description. This can reduce CTR from social referrals but has zero SEO impact.
<code>User-agent: facebookexternalhit</code> — Matching is case-insensitive. Robots.txt is fetched from the root of each subdomain separately.
facebookexternalhit is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility).Understanding facebookexternalhit's purpose helps you decide whether to allow or block it.
facebookexternalhit. This is the exact string you must use in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. User-agent matching in robots.txt is case-insensitive, but the string must be spelled correctly. You can verify that a request genuinely comes from facebookexternalhit by performing a reverse-DNS lookup on the source IP — legitimate bots resolve back to their operator's domain.facebookexternalhit is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility)./robots.txt file:
User-agent: facebookexternalhit Disallow: /This instructs facebookexternalhit not to crawl any path on your site. The Disallow: / directive covers the entire domain including subfolders. To only block specific sections, replace / with the path (e.g.,
Disallow: /blog/). Note: robots.txt is publicly readable — any bot or human can inspect it at yourdomain.com/robots.txt.facebookexternalhit (case-insensitive grep: grep -i "facebookexternalhit" /var/log/nginx/access.log). You can also check Google Search Console → Coverage → Crawl Stats for Googlebot variants. For facebookexternalhit specifically, filter by user-agent in your log analysis tool (GoAccess, AWStats, etc.).User-agent: facebookexternalhit Crawl-delay: 10(10 second delay between requests).
Disallow: / you can restrict facebookexternalhit to specific paths:
User-agent: facebookexternalhit Disallow: /private/ Disallow: /staging/ Allow: /This allows facebookexternalhit everywhere except the listed paths. Path matching in robots.txt uses prefix matching —
Disallow: /private/ blocks /private/page.html but NOT /public/private/.facebookexternalhit and ensure your pages include <meta property="og:title">, og:description, and og:image.Check instantly with our free AI Bot Checker
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