Dataset builders
Mozilla-Tabstack is a bot operated by Mozilla that crawls pages into a dataset that may be reused or shared with third parties. Tabstack is a web intelligence API for AI agents. It is documented as honouring robots.txt, but no IP range list or reverse-DNS convention is published, so a request carrying this user agent cannot be proven genuine.
Request says
"Mozilla-Tabstack"
Checked against
Nothing published
Live check
No operator check exists for Mozilla-Tabstack. This still shows what the address really is.
Reference
| User agent | Mozilla-TabstackToken only: match on the substring. |
|---|---|
| Operator | Mozilla |
| Purpose | Dataset builders |
| Respects robots.txt | Honours |
| Verification method | Claim onlyNone published, user agent only No IP range file and no reverse-DNS convention have been published for this agent. The user-agent string is the only signal, and any client can send it, so treat a match as a claim rather than proof. |
| Crawl pattern | On demand via API. |
| Robots.txt tokens | Mozilla-Tabstack |
| Operator documentation | None published |
Tabstack is a web intelligence API for AI agents. It extracts structured data from web pages and makes it available to AI agents.
robots.txt
Paste one at the root of your domain. Rules are per token.
User-agent: Mozilla-Tabstack
Disallow: /User-agent: Mozilla-Tabstack
Allow: /User-agent: Mozilla-Tabstack
Allow: /
Disallow: /account/
Disallow: /checkout/
Disallow: /searchEdit the Disallow paths to match your own URLs.
Blocking Mozilla-Tabstack keeps your pages out of the datasets it builds from future crawls. It does not remove anything collected earlier, and how each operator uses or shares its data varies, so check their policy.
Build a file for every crawlerFAQ
Mozilla-Tabstack is a bot operated by Mozilla that crawls pages into a dataset that may be reused or shared with third parties. Tabstack is a web intelligence API for AI agents. It is documented as honouring robots.txt, but no IP range list or reverse-DNS convention is published, so a request carrying this user agent cannot be proven genuine.
Yes. The operator documents that Mozilla-Tabstack reads robots.txt and follows Disallow rules for its own token. Rules take effect on the next fetch of the file, which can be hours or days after you publish them.
You cannot, at least not from the request itself. No IP range file and no reverse-DNS convention have been published for this agent. The user-agent string is the only signal, and any client can send it, so treat a match as a claim rather than proof. Compare the source IP against hosting and datacenter ranges instead, and rate limit anything that behaves like a crawler.
Add the Mozilla-Tabstack token to robots.txt with Disallow: /. If the crawler ignores robots.txt, match the user agent at your CDN or reverse proxy and return 403 there instead.
Blocking Mozilla-Tabstack keeps your pages out of the datasets it builds from future crawls. It does not remove anything collected earlier, and how each operator uses or shares its data varies, so check their policy.