See it on a real storeBots, pages and people sent by AI on an example store. No sign-up.SEO tools, run by Majestic.
What is MJ12bot? Majestic's SEO tool crawler. It can't be verified beyond its name.
Run by Majestic.
Purpose: SEO tools. A visit means an SEO tool is crawling your site, either for its own index of links and pages or because someone ran an audit or test on your site.
robots.txt name: MJ12bot.
Name only: no published list to check a visit against.
At a glance, the facts in one table.
MJ12bot at a glance. Taken from SenseGap's open bot directory, the same data that sorts every visit in the dashboard.
All bots| MJ12bot | |
|---|---|
| Operator | Majestic |
| Purpose | SEO tools |
| User agent contains | MJ12bot |
| robots.txt name | MJ12bot |
| Verification | Name only |
| Documentation | None listed |
Purpose, what it does and why it came.
What MJ12bot does. SenseGap sorts every visit by purpose. MJ12bot is in the SEO tools group.
MJ12bot is Majestic's crawler that collects data for Majestic's SEO tools.
What a visit means
A visit means an SEO tool is crawling your site, either for its own index of links and pages or because someone ran an audit or test on your site.
Detection, the header SenseGap matches.
How SenseGap recognizes MJ12bot. By its User-Agent header. A separate check then decides whether the visit is real.
Every request carries a User-Agent header naming the software that sent it. SenseGap counts a request as MJ12bot when that header contains MJ12bot, in any letter case. The header is plain text, so any script can copy it. Matching the name is where recognition starts, not where trust starts.
/MJ12bot/iVerification, how to tell a real visit from a fake.
MJ12bot can't be fully verified. SenseGap knows of no published IP ranges or DNS names for it, so the name is all there is.
How we verify botsNot beyond the user agent. SenseGap knows of no published IP ranges or DNS names for MJ12bot, so anyone can send its name. SenseGap marks these visits Unverified rather than calling them real.
robots.txt, rules you can copy.
Block or allow MJ12bot in robots.txt. Its robots.txt name is MJ12bot. Paste a group into the robots.txt at your site's root.
User-agent: MJ12bot
Disallow: /User-agent: MJ12bot
Allow: /User-agent: MJ12bot
Disallow: /private/One rule catches people out. Under the robots.txt standard (RFC 9309), a crawler that finds a group naming it follows only that group and ignores your User-agent: * rules. If you add a MJ12bot group, repeat in it anything from the catch-all group you still want applied.
robots.txt is a request, not a lock. To enforce a block, match the User-Agent header at your server or CDN. In nginx:
# nginx, inside a server block
if ($http_user_agent ~* "MJ12bot") {
return 403;
}SenseGap reads your robots.txt and shows, bot by bot, what you allow and which bots fetched pages you disallowed. See what you get.
Trade-off, what blocking changes.
Should you block MJ12bot? It depends on what you want from Majestic. Here is what each choice means.
If you allow it
Your site's data in the tool stays complete, and audits you run with it keep working.
If you block it
The tool's picture of your site becomes incomplete, and its audits of your site may fail. It has no effect on how search engines rank you.
SEO tools, other bots with the same job.
Other SEO tool crawlers. Same purpose, different companies.
Browse the directoryFAQ, MJ12bot in short answers.
MJ12bot, answered plainly
What is MJ12bot?
MJ12bot is Majestic's crawler that collects data for Majestic's SEO tools.
Who runs MJ12bot?
Majestic. SenseGap's directory has no documentation link for it yet.
What does a visit from MJ12bot mean?
A visit means an SEO tool is crawling your site, either for its own index of links and pages or because someone ran an audit or test on your site.
What user agent does MJ12bot use?
Its User-Agent header contains "MJ12bot". SenseGap matches it regardless of letter case.
How do I block MJ12bot?
Add "User-agent: MJ12bot" followed by "Disallow: /" to your robots.txt. robots.txt is a request, not a lock; to enforce it, block the user agent at your server or CDN.
Can I verify that a visit is really MJ12bot?
Not beyond the user agent. SenseGap knows of no published IP ranges or DNS names for MJ12bot, so anyone can send its name. SenseGap marks these visits Unverified rather than calling them real.
Does Majestic publish IP ranges for MJ12bot?
No. SenseGap knows of no published list of addresses for MJ12bot.
What happens if I block MJ12bot?
The tool's picture of your site becomes incomplete, and its audits of your site may fail. It has no effect on how search engines rank you.