MJ12bot
Majestic's SEO crawler building the largest commercial link index.
What is MJ12bot?
MJ12bot is the web crawler for Majestic, an SEO tool provider known for having one of the largest commercial link indexes. Majestic focuses specifically on backlink data, offering Trust Flow and Citation Flow metrics used by SEO professionals.
The crawler can be moderately aggressive and has been known to generate significant crawl traffic on some sites. It identifies itself clearly and respects robots.txt, including crawl-delay directives.
Majestic's specialization in link data means MJ12bot is primarily interested in discovering and analyzing links on your pages rather than content. Allowing or blocking it mainly affects the accuracy of your site's data in Majestic's tools.
User-Agent Strings
These are the known user-agent patterns used by MJ12bot. Use them to identify this crawler in your server logs or configure robots.txt rules.
robots.txt example:
User-agent: MJ12bot Disallow: /private/ Allow: /
How to Manage MJ12bot
Primarily interested in links, not content.
Can be moderately aggressive — use crawl-delay if needed.
Blocking won't affect rankings but may limit Majestic data about your site.
Use Switch to set appropriate crawl rate limits.
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