Meta-ExternalAds

Meta documents Meta-ExternalAds as a crawler used “for use cases such as improving advertising and other business-related products” — an advertising/validation-purpose crawler, distinct from Meta’s AI training and search crawlers.

A note on the token

Meta’s own documentation writes the literal user-agent string in lowercase, meta-externalads/1.1. robots.txt user-agent matching is case-insensitive (RFC 9309 §2.2.1), so this does not change how a Disallow rule applies.

Site-owner controls

Disallowing Meta-ExternalAds affects only Meta’s advertising- and business-product-related crawling of this content. It does not affect Meta-ExternalAgent (AI training), Meta-WebIndexer (search), or Meta-ExternalFetcher (user-triggered agent fetches) — Meta documents each as a separate token, and CrawlPact evaluates them independently. See /limitations for what a robots.txt rule can and cannot guarantee.

Example robots.txt configuration

To disallow Meta-ExternalAds specifically, without affecting any other crawler:

User-agent: Meta-ExternalAds
Disallow: /

If no dedicated User-agent: Meta-ExternalAds group exists in a domain'srobots.txt, this crawler falls back to whatever the wildcard User-agent: * group says (RFC 9309) — see robots.txt syntax basics for how group selection works. A robots.txt rule is a published instruction; it does not technically prevent access.

Official source

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

Verified against the source above as of 24 July 2026 — see how CrawlPact verifies crawler information.