Mozilla Tabstack
SafeUser-agent: Mozilla-Tabstack
Category: AI & LLM Bots
SEO impact if blocked: 2/10
Mozilla
1 crawler operated by Mozilla
https://www.mozilla.org/Who Mozilla is, for site owners
Mozilla operates 1 crawler in our directory, filed under AI & LLM Bots. Its crawl behaviour is rated safe.
Blocking Mozilla carries an SEO impact score of 2/10. Blocking impact is rated: Low - No SEO ranking impact.
Our recommendation for Mozilla: Generally safe to allow; provides legitimate crawling value.
Mozilla at a glance
| Operator | Mozilla |
|---|---|
| Crawler in directory | 1 |
| Categories | AI & LLM Bots |
| SEO impact if blocked | 2/10 |
| Crawl behaviour | 1 rated safe |
| Website | www.mozilla.org |
| Official crawler docs | Mozilla crawler documentation |
Crawler operated by Mozilla
How to block or allow Mozilla in robots.txt
This rule covers the single crawler Mozilla operates. Add it to the robots.txt file at the root of your domain.
Block Mozilla completely
User-agent: Mozilla-Tabstack
Disallow: /
Allow Mozilla explicitly
User-agent: Mozilla-Tabstack
Allow: /
robots.txt is a request, not an enforcement mechanism. A crawler that ignores it needs a block at the server or CDN layer. Rules are case-sensitive on the path and matched against the user-agent token, not the full user-agent string.
Frequently asked questions about Mozilla
What crawler does Mozilla run?
Mozilla operates 1 crawler in our directory: Mozilla Tabstack (user-agent Mozilla-Tabstack).
Should I block Mozilla?
Generally safe to allow; provides legitimate crawling value. The SEO impact score for blocking is 2/10, where 10 means blocking costs you the most visibility.
How do I block Mozilla in robots.txt?
Add the following to robots.txt at your domain root: User-agent: Mozilla-Tabstack then Disallow: /.
Does blocking Mozilla hurt my search rankings?
Blocking impact is rated: Low - No SEO ranking impact. Google's own ranking crawler is Googlebot, which this operator does not run, so blocking Mozilla does not by itself remove you from Google's index. What it can change is whether AI assistants and analytics tools can read your pages.