Meta-ExternalFetcher

Operator

Meta

Type

Social Media Agent

Official page

developers.facebook.com

robots.txt token

meta-externalfetcher, Meta-ExternalFetcher

Follows robots.txt

Partly, according to Meta.

In Vireo

Excluded, reported under Link previews

What it does

Fetches individual links when a user asks, including for AI features that browse sites on a user's behalf.

The Meta-ExternalFetcher crawler fetches individual links at a user’s request and supports product functions such as evaluating and improving agentic AI capabilities

Meta

User agent

Requests from Meta-ExternalFetcher carry user agents like these:

meta-externalfetcher/1.1

meta-externalfetcher/1.1 (+https://developers.facebook.com/docs/sharing/webmasters/crawler)

Device Detector identifies it with this pattern (a case-insensitive regular expression):

meta-externalfetcher

Anyone can put any name in a user agent. Where the operator publishes IP ranges, checking the request's address against them is the way to confirm a visit is genuine.

How to block or allow Meta-ExternalFetcher

Add a group for its tokens to the robots.txt file at the root of your site. To keep it out of the whole site:

User-agent: meta-externalfetcher
User-agent: Meta-ExternalFetcher
Disallow: /

To let it crawl everything, use an empty Disallow: or Allow: / instead. WordPress serves a virtual robots.txt that many SEO plugins let you edit. A real robots.txt file uploaded to the site root takes its place.

The Meta-ExternalFetcher crawler may bypass robots.txt because it performs fetches that were requested by the user.

Meta

robots.txt is a request, so it only works on crawlers that honour it. A bot that ignores it has to be blocked at the server or firewall, by user agent or IP address.

Worth knowing

User-initiated, so robots.txt may not stop it.

Accordingly, this crawler may bypass robots.txt rules.

Meta

How Vireo counts Meta-ExternalFetcher

Vireo keeps requests from Meta-ExternalFetcher out of your pageviews and visitors and counts them on its bot report under Link previews, so you can see how much it left out rather than wonder why your server logs show more traffic.

Checked by running Vireo Analytics' own bot filter over Meta-ExternalFetcher's user agents.

Sources

• Meta: crawler documentation (checked October 2026)
• Meta-ExternalFetcher information page (developers.facebook.com)
• Matomo Device Detector, bots.yml (LGPL-3.0)
• ai.robots.txt (MIT)