facebookexternalhit
Meta · Other bots · User agent + IP range
About this crawler
Fetches shared links to build previews on Facebook, Instagram and Messenger.
Usually means: A product is checking the page for a specific job: an ad review, a link preview, a feed or an SEO index.
User agent
facebookexternalhit
MetricRaven matches this token anywhere in the request's user agent, ignoring case. Operators add version numbers and browser text around it, for example "facebookexternalhit/1.0".
IP verification
Verified when the user agent and the IP range both match
1User agent
The request's user agent contains
facebookexternalhit.2Request IP
Your server-side tracker sends the IP that made the request.
3Range check
The IP is compared with the ranges Meta publishes, refreshed twice a day.
Range sources
Meta network (AS32934)
https://stat.ripe.net/data/announced-prefixes/data.json?resource=AS32934
Meta doesn't publish crawler-specific ranges; this is the network it announces, so a match means the request came from Meta's infrastructure.
Control it in robots.txt
User-agent: facebookexternalhit Disallow: /private/
Well-behaved crawlers re-read robots.txt within a day or so.
Questions
- What is facebookexternalhit?
- Fetches shared links to build previews on Facebook, Instagram and Messenger. MetricRaven groups it under Other bots: ad checks, link previews, feed readers, SEO tools and other bots.
- How do I verify that a request really comes from facebookexternalhit?
- Check both the user agent and the IP. Requests from facebookexternalhit contain "facebookexternalhit" in the user agent and come from the IP ranges Meta publishes (https://stat.ripe.net/data/announced-prefixes/data.json?resource=AS32934). A request with the name but another IP is likely spoofed.
- How do I block or allow facebookexternalhit?
- Add a robots.txt group for "facebookexternalhit" with the paths to allow or disallow. Fetchers that act for a user may ignore robots.txt; block those at your server or firewall instead.
- How can I see when facebookexternalhit visits my website?
- Most crawlers never run JavaScript, so browser analytics miss them. MetricRaven's @metricraven/ai-crawl package reports crawler requests from your server, verifies their IPs against published ranges, and shows which pages each crawler reads.
See when AI assistants and crawlers read your site
Add one line to your server and MetricRaven shows which assistants, search engines and training crawlers request your pages, which ones are IP-verified, and the URLs they expected to find, including 404s.