See it on a real storeBots, pages and people sent by AI on an example store. No sign-up.Answering a person, run by Meta.
What is Meta-ExternalFetcher? Meta's fetcher for people's AI questions. It can't be verified beyond its name.
Run by Meta.
Purpose: Answering a person. A visit means a person asked an AI assistant something, and the assistant opened this page to answer.
robots.txt name: Meta-ExternalFetcher.
Name only: no published list to check a visit against.
At a glance, the facts in one table.
Meta-ExternalFetcher at a glance. Taken from SenseGap's open bot directory, the same data that sorts every visit in the dashboard.
All bots| Meta-ExternalFetcher | |
|---|---|
| Operator | Meta |
| Purpose | Answering a person |
| User agent contains | meta-externalfetcher |
| robots.txt name | Meta-ExternalFetcher |
| Verification | Name only |
| Documentation | None listed |
Purpose, what it does and why it came.
What Meta-ExternalFetcher does. SenseGap sorts every visit by purpose. Meta-ExternalFetcher is in the Answering a person group.
Meta-ExternalFetcher is Meta's fetcher that opens a page when a person asks Meta AI something that needs it.
What a visit means
A visit means a person asked an AI assistant something, and the assistant opened this page to answer. It is the one kind of AI visit that implies a real question behind it.
That is why SenseGap pays close attention to this kind of visit. It groups the pages assistants open together to estimate what people likely asked, always labeled as an estimate. Nobody can see the actual questions. How it works.
Detection, the header SenseGap matches.
How SenseGap recognizes Meta-ExternalFetcher. By its User-Agent header. A separate check then decides whether the visit is real.
Every request carries a User-Agent header naming the software that sent it. SenseGap counts a request as Meta-ExternalFetcher when that header contains meta-externalfetcher, in any letter case. The header is plain text, so any script can copy it. Matching the name is where recognition starts, not where trust starts.
/meta-externalfetcher/iVerification, how to tell a real visit from a fake.
Meta-ExternalFetcher can't be fully verified. SenseGap knows of no published IP ranges or DNS names for it, so the name is all there is.
How we verify botsNot beyond the user agent. SenseGap knows of no published IP ranges or DNS names for Meta-ExternalFetcher, so anyone can send its name. SenseGap marks these visits Unverified rather than calling them real.
robots.txt, rules you can copy.
Block or allow Meta-ExternalFetcher in robots.txt. Its robots.txt name is Meta-ExternalFetcher. Paste a group into the robots.txt at your site's root.
User-agent: Meta-ExternalFetcher
Disallow: /User-agent: Meta-ExternalFetcher
Allow: /User-agent: Meta-ExternalFetcher
Disallow: /private/One rule catches people out. Under the robots.txt standard (RFC 9309), a crawler that finds a group naming it follows only that group and ignores your User-agent: * rules. If you add a Meta-ExternalFetcher group, repeat in it anything from the catch-all group you still want applied.
robots.txt is a request, not a lock. To enforce a block, match the User-Agent header at your server or CDN. In nginx:
# nginx, inside a server block
if ($http_user_agent ~* "meta-externalfetcher") {
return 403;
}SenseGap reads your robots.txt and shows, bot by bot, what you allow and which bots fetched pages you disallowed. See what you get.
Trade-off, what blocking changes.
Should you block Meta-ExternalFetcher? It depends on what you want from Meta. Here is what each choice means.
If you allow it
The assistant can read your page while it answers, quote it and link to it.
If you block it
The assistant cannot open your page when someone asks, so it answers from other sources, or from what it already knows about you.
Meta, every bot it runs.
More bots from Meta. Meta runs 5 bots in the directory, each with its own job.
Answering a person, other bots with the same job.
Other bots that answer people. Same purpose, different companies.
Browse the directoryFAQ, Meta-ExternalFetcher in short answers.
Meta-ExternalFetcher, answered plainly
What is Meta-ExternalFetcher?
Meta-ExternalFetcher is Meta's fetcher that opens a page when a person asks Meta AI something that needs it.
Who runs Meta-ExternalFetcher?
Meta. SenseGap's directory has no documentation link for it yet.
What does a visit from Meta-ExternalFetcher mean?
A visit means a person asked an AI assistant something, and the assistant opened this page to answer. It is the one kind of AI visit that implies a real question behind it.
What user agent does Meta-ExternalFetcher use?
Its User-Agent header contains "meta-externalfetcher". SenseGap matches it regardless of letter case.
How do I block Meta-ExternalFetcher?
Add "User-agent: Meta-ExternalFetcher" followed by "Disallow: /" to your robots.txt. robots.txt is a request, not a lock; to enforce it, block the user agent at your server or CDN.
Can I verify that a visit is really Meta-ExternalFetcher?
Not beyond the user agent. SenseGap knows of no published IP ranges or DNS names for Meta-ExternalFetcher, so anyone can send its name. SenseGap marks these visits Unverified rather than calling them real.
Does Meta publish IP ranges for Meta-ExternalFetcher?
No. SenseGap knows of no published list of addresses for Meta-ExternalFetcher.
What happens if I block Meta-ExternalFetcher?
The assistant cannot open your page when someone asks, so it answers from other sources, or from what it already knows about you.