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AI crawler · Meta

Meta-ExternalAgent

Meta-ExternalAgent crawls the web for Meta's AI models and products. Collects pages to train models; blocking it does not affect whether AI can answer about you today.

By Reflexa Technologies — the team building Reflexa, the agent that works on your site · updated 16 October 2026

What Meta-ExternalAgent is

Meta-ExternalAgent crawls the web for Meta's AI models and products. It is distinct from facebookexternalhit, which fetches link previews when someone shares a page.

What it does with your pages

Training: collects pages to train models; blocking it does not affect whether AI can answer about you today.

How it identifies itself

User-agent string:

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

robots.txt token: Meta-ExternalAgent. Documented: honours robots.txt.

How to verify it

Meta publishes no IP-range feed for Meta-ExternalAgent; Meta publishes its crawler IP ranges via its developer documentation. Treat the user-agent as a claim, and rate-limit or block by behaviour if it misbehaves.

What blocking it means

Blocking Meta-ExternalAgent keeps your pages out of Meta's AI crawl. Do not block facebookexternalhit by mistake — that breaks link previews on Facebook and Instagram.

Vendor documentation

https://developers.facebook.com/docs/sharing/webmasters/web-crawlers/

Check your site: the AI Crawler Access Check reads your robots.txt for Meta-ExternalAgent and the other AI crawlers and fetches your homepage with each one's real user-agent — the CDN challenge that robots.txt cannot show.

Other crawlers

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Questions people ask.

Should I block Meta-ExternalAgent?

Blocking Meta-ExternalAgent keeps your pages out of Meta's AI crawl. Do not block facebookexternalhit by mistake — that breaks link previews on Facebook and Instagram.

How do I allow Meta-ExternalAgent in robots.txt?

Add a group for it: User-agent: Meta-ExternalAgent on one line and Allow: / on the next. If a User-agent: * group has a Disallow, the named group takes precedence for Meta-ExternalAgent.

How do I block Meta-ExternalAgent?

User-agent: Meta-ExternalAgent then Disallow: /. Meta documents that Meta-ExternalAgent honours robots.txt.

How do I verify a request is really Meta-ExternalAgent?

Meta publishes no IP-range feed for Meta-ExternalAgent; Meta publishes its crawler IP ranges via its developer documentation. Treat the user-agent as a claim, and rate-limit or block by behaviour if it misbehaves.

Is Meta-ExternalAgent allowed on your site?

The free crawler check reads your robots.txt per bot and fetches your homepage with each one's real user-agent.

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