FacebookExternalHit
FacebookExternalHit is a single-page fetcher operated by Meta. It fetches one page (or a small set) when triggered by a user action, typically a link being shared on social media, a messaging app, or an RSS reader.
Volume tracks shares and clicks rather than crawl schedules. A trending link can produce a sudden spike, but FacebookExternalHit will not crawl the rest of your site.
Blocking it usually means the link previews on the corresponding platform stop showing your title, image, and description.
See FacebookExternalHit on your own site
Match the User-Agent header on incoming requests against the pattern below.
regex
Verify by IP
For higher confidence, also verify the source IP against the operator's published ranges. UA strings can be spoofed; IP ownership is harder to fake.
Renders JavaScript
No
IP verification
Published IP ranges
Crawl frequency
Per user action
Honors robots.txt
Yes
Honors Crawl-delay
Varies
Meta runs 16 bots in total. Each one is a separate user-agent so you can allow or block them independently.
Link Unfurler
9- FacebookExternalHitYou are here
- Facebot
- Threadbot
- FacebookExternalUserAgent
- Threadsbot
- FacebookCatalog
Training Crawler
3Live-Fetch AI
2AI Search Index
1SEO Crawler
1Share of AI bot traffic
4.8%
↓ 17% vs 12 mo ago
% of top sites blocking it
0.70%
↑ 75% vs 12 mo ago
Top page categories crawled
Link Unfurlers as a category, share of all bot traffic
15%
↑ 3% vs 12 mo ago
Sum of every link unfurler we have public stats on. Compare to FacebookExternalHit's individual trend above to see if it's pulling ahead of its category or falling behind.
Crawl-to-click ratio
8 : 1
For every 1,000 fetches, this agent sends ~125 human visits back. Cloudflare crawl-to-click data
Snapshot updated
2026-04
Connect Agent Analytics for daily, per-site numbers.
Source: Meta crawler documentation (developers.facebook.com), Cloudflare Radar verified bots
Should I let FacebookExternalHit through?
In most cases, yes. Fetchers power link previews and feed readers. Blocking breaks the user experience on social and messaging platforms. If volume gets noisy, rate-limit it before you block it outright.
Does blocking FacebookExternalHit affect my Google rankings?
No. FacebookExternalHit is not a search-engine crawler. Your ranking on Google or Bing is unaffected by what you do here.
How do I confirm a request is really from FacebookExternalHit?
Two checks. The User-Agent header should match a known FacebookExternalHit string, and the request's source IP should fall inside Meta's published ranges. The User-Agent alone is trivially spoofable, so the IP check is what gives you confidence. Meta publishes the ranges so you can validate at the CDN or edge.
What breaks if I block FacebookExternalHit?
Link previews, embeds, and unfurls on whatever surface FacebookExternalHit feeds will stop rendering. Users sharing your URLs into Meta will see a bare link instead of a rich card. Usually that's the first thing people regret blocking.
How is FacebookExternalHit different from Meta's other bots?
Meta splits work across multiple user-agents so site owners can decide on each one independently. Training crawlers, live-fetch agents, search indexers, and agentic browsers each get their own name. Worth scanning the rest of the Meta family above to see which ones actually matter for your site.
What's the cleanest way to control FacebookExternalHit?
Two layers. Robots.txt for the polite crawlers that read it, and rules at your CDN or edge for the ones that don't. Rankly's Agent Experience handles both from a single config, so you can allow, block, rate-limit, or serve a stripped-down version per bot. Agent Analytics handles the observation half so you know which bots are actually worth a rule.
Verify everything above against the operator's own documentation.