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What is FacebookExternalHit?

Direct Answer: Facebook External Hit crawler scrapes content from the web to generate link previews when URLs are shared on Facebook, Messenger, and other Meta platforms.

Operator: Meta Type: Social Media Bot Purpose: Link preview generation

FacebookExternalHit is Meta's crawler that fetches web pages to generate Open Graph previews when links are shared on Facebook, Instagram, Messenger, and other Meta services. It reads og:title, og:description, og:image, and other Open Graph meta tags to build link previews. Blocking this bot means shared links on Meta platforms will not show previews.

User-Agent Identification

The following user-agent strings identify FacebookExternalHit in your live traffic data:

  • facebookexternalhit/1.1

robots.txt Rules for FacebookExternalHit

Respects robots.txt: No

Use the following robots.txt rules to control FacebookExternalHit access:

# Block FacebookExternalHit
User-agent: facebookexternalhit
Disallow: /

# Allow FacebookExternalHit
User-agent: facebookexternalhit
Allow: /

This bot does not commit to following robots.txt

FacebookExternalHit does not officially follow robots.txt directives. The only reliable way to control access is through server-side blocking (IP filtering, user-agent rules in your web server config) combined with log monitoring to verify effectiveness.

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Crawl Behavior

Request Pattern:Not documented

Official Documentation Quotes

"Facebook allows its web crawler, facebookexternalhit, to access your website to scrape and cache your content."

Crawl Activity Index

Relative crawl activity for FacebookExternalHit over the past 28 days. Higher values indicate increased crawling intensity compared to the period baseline.

View recent activity data (last 7 days)
Date Activity Index
Mar 26, 2026 88.0
Mar 27, 2026 82.7
Mar 28, 2026 83.1
Mar 29, 2026 81.8
Mar 30, 2026 87.3
Mar 31, 2026 90.2
Apr 1, 2026 88.9

Source: Cloudflare Radar

Why track FacebookExternalHit traffic?

Ensure your link previews render correctly. FacebookExternalHit fetches your pages to generate link preview cards on Meta. If it can't access your meta tags, your shared links display broken or generic previews.

Monitor social sharing activity. FacebookExternalHit requests correlate with how often your URLs are being shared on Meta, even before engagement metrics are available.

Log Verification

To verify FacebookExternalHit traffic in your live traffic data:

  1. Search access logs for the user-agent strings listed above
  2. Check if the IP addresses match documented ranges (if provided by Meta)
  3. Verify the crawl pattern matches documented behavior
  4. Use reverse DNS lookup for additional verification if available

Note: Observed behavior in production environments may differ from official documentation. Live traffic monitoring provides the only reliable verification of actual bot behavior.

Undocumented Information

The following information is not officially documented for FacebookExternalHit:

  • crawl rate
  • scraping scope

Verify your link previews work — and track social bot access

  • Confirm FacebookExternalHit can access your Open Graph meta tags
  • Track which URLs are being shared on Meta
  • Detect failed fetches causing broken preview cards
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Official Documentation

View Official FacebookExternalHit Documentation →

Information sourced from official documentation. Content generated with AI assistance.