Meta
meta-webindexer
Crawls pages to improve Meta AI search results.
AI searchLink previews
facebookexternalhit
Retrieves previews of links shared in Meta apps.
Operated by Meta
See your agent traffic PurposeLink previews
HTTP identifierfacebookexternalhit
IdentityVerify beyond the name
THE SIGNAL
What this visit tells you
A preview fetch can precede a visit or happen without one.
Shared URLs
Image responses
Preview fetch errors
Your next move
Check the shared page’s Open Graph title and image using Meta’s Sharing Debugger.
The technical details
MarkdownHow to identify it
Look for the facebookexternalhit identifier in a request’s User-Agent. This is a name match, not identity verification. Version strings may change.
How to check identity
A User-Agent match identifies a claimed client. Check the source IP and any operator-published verification method before granting access.
Access and robots.txt
Meta documents robots.txt controls, but FacebookExternalHit may bypass them for security or integrity checks.
Optional full-site opt-out. Merge with existing rules only if intended. robots.txt does not secure private content.
User-agent: facebookexternalhit
Disallow: /Seeing 403 or 404 responses?
403 means access was denied; 404 means the resource was not found. Compare the public path, request time, edge security event and origin response to find the cause.
Separate intended restrictions and secret-file probes from pages that should work. A User-Agent name alone does not justify allowing a request.
SourcesReviewed 2026-09-14
Identity and purpose are based on these sources. Analytics interpretation and suggested checks are Apostl guidance.
APOSTL PulseSee facebookexternalhit in context
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Different bots, different intent
Meta
meta-externalagent
Collects content for uses including Meta AI training.
AI trainingMeta
meta-externalfetcher
Fetches external pages for user actions in Meta products.
User-requested fetch