CrawlCheck

AI crawlers · SEO and research crawlers

MJ12bot

MJ12bot is the tool or developer fetch run by Majestic: Majestic link index. Its operator publishes no IP ranges or DNS names for it, so a request carrying this name cannot be verified. Treat the name in a log line as a claim.

User-agent tokenMJ12bot
OperatorMajestic
What it doesMajestic link index
Kindtool or developer fetch
Can a request be verified?No — user agent string only
In a CrawlCheck scanRead from robots.txt; reported, never scored

Allow or block it in robots.txt

User-agent: MJ12bot
Disallow: /
User-agent: MJ12bot
Allow: /

Add a group that names it: "User-agent: MJ12bot" followed by "Disallow: /". A crawler follows only the most specific group that names it, so once a group names MJ12bot, rules under "User-agent: *" no longer apply to it; repeat in that group any Disallow lines you still want.

What blocking it changes

No. It is a third-party tool's crawler. Blocking it changes what that tool knows about your site, not anyone's AI answers.

See what MJ12bot and every other named agent receive from your own site: run a free scan. The full catalogue is on AI crawlers and as JSON at /ai-crawlers.json.

Questions about MJ12bot

QHow do I block MJ12bot in robots.txt?
Add a group that names it: "User-agent: MJ12bot" followed by "Disallow: /". A crawler follows only the most specific group that names it, so once a group names MJ12bot, rules under "User-agent: *" no longer apply to it; repeat in that group any Disallow lines you still want.
QHow can I tell if a request from MJ12bot is real?
Its operator publishes no IP ranges or DNS names for it, so a request carrying this name cannot be verified. Treat the name in a log line as a claim.
QDoes blocking MJ12bot affect whether my site appears in AI answers?
No. It is a third-party tool's crawler. Blocking it changes what that tool knows about your site, not anyone's AI answers.
QDoes CrawlCheck test my site as MJ12bot?
Not as a request. CrawlCheck reads the rules your robots.txt sets for MJ12bot and reports them. Rules for it are reported and never scored, because refusing it is a policy choice.