MJ12bot — Majestic's web crawler
MJ12bot is the crawler behind Majestic's backlink index. It is notable for being distributed — run across many independent operators — rather than a single central crawl. It uses the MJ12bot robots.txt token and is documented as honouring robots.txt.
What this means
MJ12bot is the crawler that builds the backlink index used by Majestic. A distinguishing feature is that the crawl is distributed: it has historically run across many independent participants rather than from a single central infrastructure.
That distributed design means MJ12bot requests can come from a wide range of sources, which complicates IP-based verification compared with a centrally operated crawler.
robots.txt considerations
Majestic documents that MJ12bot honours robots.txt and supports crawl-delay. To control it, target the MJ12bot token. Because of the distributed model, rely on the documented token and robots.txt handling rather than expecting a single published IP range.
- robots.txt token: MJ12bot
- Distributed backlink-index crawler (Majestic)
- Documented to honour robots.txt and crawl-delay
How it appears in analytics and logs
A request carrying the MJ12bot token is Majestic's backlink-index crawler fetching a URL — a bot event from a third-party tool, not a search engine and not a human visit. Because it is distributed, requests can originate from many sources.
Diagnostic use case
Recognise MJ12bot as a third-party backlink crawler and control it via robots.txt using its token.
What WebmasterID can help detect
WebmasterID classifies MJ12bot server-side as an SEO crawler and shows its activity separately from human traffic and search-engine crawlers, so third-party crawling is visible without log parsing.
Common mistakes
- Expecting a single central IP range — MJ12bot is distributed.
- Treating backlink-crawl hits as human visits.
- Assuming MJ12bot crawling affects search rankings — it does not.
Privacy and accuracy notes
Identification uses the user agent — no human identity. WebmasterID records MJ12bot as a bot event, separate from human analytics.
Related pages
- DotBot — Moz's web crawler
DotBot is the crawler operated by Moz to build its link index, which powers Moz's link-analysis tools. It is a third-party crawler, not a search engine. It uses the DotBot robots.txt token and is documented as honouring robots.txt.
- AhrefsBot — Ahrefs SEO crawler
AhrefsBot is the crawler operated by Ahrefs to build its SEO and backlink index. It is a third-party crawler, not a search engine, so it does not affect Google or Bing rankings directly. It uses the AhrefsBot robots.txt token and is documented as respecting robots.txt and crawl-delay.
- Bot vs human
Separate automated crawlers from real human visits.
Sources and verification notes
- Majestic — MJ12bot documentationDocuments MJ12bot, its distributed model, and robots.txt handling.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.