Meta-WebIndexer
Meta · Answer index · robots.txt token meta-webindexer
1% of 30,177 measured domains disallow meta-webindexer in robots.txt at the site root. Separately, and independently of robots.txt, 17.4% of 30,187 reachable domains refuse an AI crawler user agent at the network edge on two consecutive probes from different locations - a refusal the site's own robots.txt does not declare and its owner often has not chosen.
Measured 2026-10-06 by direct request to every domain in the corpus. Method: how this is measured. Reuse under CC BY 4.0 with attribution.
Cite as: Crawl Census, "Meta-WebIndexer blocking rate", measured 2026-10-06. https://crawlcensus.com/bot/meta-webindexer
What it is definition
Indexes pages so Meta AI can cite and link them in its search answers.
Meta-WebIndexer is operated by Meta and classified here as answer index. These agents build the index an answer engine queries at question time. Disallowing one removes the site from those answers and from the citations that link back to it. Training is governed by separate tokens, so this is the expensive block, not the protective one.
Disallowing meta-webindexer removes the site from the index Meta's AI products queries when it answers a question. The engine can then neither quote nor link the page, which is a traffic decision rather than a licensing one. Model training is governed by separate tokens.
- robots.txt token
- meta-webindexer
- Operator
- Meta
- Purpose
- Answer index
- Honors robots.txt
- yes
- Documentation
- https://developers.facebook.com/docs/sharing/webmasters/web-crawlers/
Identity on the wire exact string
meta-webindexer/1.1 (+https://developers.facebook.com/docs/sharing/webmasters/web-crawlers)curl -A 'meta-webindexer/1.1 (+https://developers.facebook.com/docs/sharing/webmasters/web-crawlers)' https://example.com/Replace the host with your own. A 403, a challenge page or an empty body means the edge is blocking the agent whatever robots.txt says.
How to allow it, how to block it robots.txt
User-agent: meta-webindexer
Allow: /Absent any rule, the agent is already allowed, so this group only matters when your * group disallows something. Naming the agent replaces the * group for it entirely, so repeat here every disallow you still want to apply to it.
User-agent: meta-webindexer
Disallow: /Disallowing meta-webindexer removes the site from the index Meta's AI products queries when it answers a question. The engine can then neither quote nor link the page, which is a traffic decision rather than a licensing one. Model training is governed by separate tokens.
Sites that block it 60 shown
See every measured domain that blocks Meta-WebIndexer
This list is served from a cache rebuilt just now. It is discarded the moment a rescan records a policy change for this agent, so a site that has just changed its robots.txt will drop off it within one scan rather than waiting for the cache to expire.
Compare Meta
Meta runs 6 agents in this registry, and they do different jobs. Blocking one says nothing about the others.
Common questions answered
Does blocking Meta-WebIndexer remove me from Meta's AI products?
Yes, in effect. Meta-WebIndexer builds the index Meta's AI products reads at question time, so disallowing it takes the site out of those answers and out of the citations that link back to it. This is the block that costs traffic.
How do I verify Meta-WebIndexer requests are genuine?
Meta's crawlers originate from AS32934, and Meta documents querying that ASN to obtain the current ranges. Map the source address to its ASN and check for AS32934. There is no published reverse DNS name.
Check your own site free
See whether your robots.txt admits Meta-WebIndexer today, and whether your edge agrees with it.