MJ12bot

What MJ12bot does

MJ12bot builds Majestic's link intelligence index using a distributed architecture: crawling runs on many independent nodes, so requests come from scattered residential and hosting IPs. It honors robots.txt, though its distributed nature means directive changes can take longer to propagate.

Why it visits your site

Link-graph data for Majestic's SEO products.

The bigger picture: SEO tool crawlers

SEO tool crawlers are commercial data harvesters with a twist: the product they build from your pages - link graphs, keyword data, authority metrics - is one your own marketing team may pay to use. They are consistently among the highest-volume non-search crawlers on the web, and they send you nothing directly. The trade is indirect: tolerate the crawl and the industry's measurement layer, including your own dashboards, stays complete.

These crawlers are generally well-behaved - documented, robots-compliant, honoring crawl-delay - so the decision is genuinely yours to make on resource and privacy grounds. Sites that block them typically do it to deny competitors easy backlink intelligence or to trim server load; sites that allow them are usually buying the completeness of their own tooling.

Should you block it?

It is legitimate but noisy in logs because of the IP spread. If you don't use Majestic data, blocking by user agent is simple and costless.

Block via robots.txt

Add these lines to the robots.txt at your site root to ask MJ12bot to stay away:

User-agent: MJ12bot
Disallow: /

Remember that robots.txt is a request, not a lock - compliance is voluntary, and enforcement happens at the server. Viz's AI Control pairs robots.txt rules with server-level 403 responses and then probes your site to verify the block is actually holding.

How to see MJ12bot traffic on your site

You have three windows onto it, each with a catch. Raw hosting access logs contain every MJ12bot request, but many managed WordPress hosts don't expose them, and when they do you are grepping text files by hand. A CDN dashboard sees the traffic at the edge, but it lives outside WordPress and speaks in totals, not in your site's terms. And JavaScript analytics - GA4 and friends - will never show it at all, because MJ12bot doesn't run scripts.

Viz's answer is the request log: filter to MJ12bot and read exactly which URLs it fetched and when, right inside wp-admin - then watch the same filter after any blocking decision to see whether the visits stopped, slowed, or kept coming.