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MJ

MJ12bot/v1.4.8

UndecidedCommunity-sourced

MJ12bot/v1.4.8 is a web crawler developed by Majestic-12 Ltd, a UK-based company specializing in search engine technologies. This bot is designed to map the link relationships between websites, contributing to the creation of a comprehensive search engine. It operates by crawling the web and collecting data on website interconnections, which is then used to build a public backlinks index accessible through Majestic's Site Explorer. The MJ12bot/v1.4.8 user agent string is: Mozilla/5.0 (compatible; MJ12bot/v1.4.8; http://mj12bot.com/) This indicates that the bot identifies itself as MJ12bot version 1.4.8 and provides a link to its official website for more information. ( user-agents.net ) MJ12bot adheres to the robots.txt standard, allowing website owners to control its access to their sites. To block MJ12bot from crawling a website, the following directive can be added to the site's robots.txt file: This instructs MJ12bot to refrain from accessing any pages on the site. For more detailed information about MJ12bot and its functionalities, you can visit its official website at mj12bot.com . Operated by Majestic-12 Ltd.

Undecided
Assessment
SEO
Category
Bot
Kind
1
Data sources
AI-generated summary, drawn from Cloudflare, operator docs, and community data

What is MJ12bot/v1.4.8?

MJ12bot is the primary web crawler for Majestic, a UK-based company that provides link intelligence and SEO data. Unlike general-purpose search engines, MJ12bot focuses specifically on mapping the hyperlink structure of the internet to power the Majestic Site Explorer. It operates as a distributed crawler, utilizing a network of nodes to maintain one of the largest and most frequently updated backlink databases in the industry.

Helpful — It is a well-documented, industry-standard crawler used by SEO professionals and webmasters to analyze link intelligence and site authority.

Identification

Bot name
MJ12bot/v1.4.8
Operator
Majestic-12 Ltd
Category
SEO
Verification
Community-sourced
User-agent string
Mozilla/5.0 (compatible; MJ12bot/v1.4.8; http://mj12bot.com/)
Main use cases
Backlink analysisSEO link intelligenceWeb graph mapping

Why it crawls your site

The bot crawls the web to identify and record the relationships between websites, specifically tracking how pages link to one another. This data is processed to calculate proprietary metrics like Trust Flow and Citation Flow, which help businesses understand their site's authority and link profile. Website owners can verify the bot's identity by checking the user-agent string against the official documentation at mj12bot.com or by performing a reverse DNS lookup on the originating IP address.

IP ranges

Requests from MJ12bot/v1.4.8 originate from these published ranges. For strict verification, match the source IP against this list in addition to checking the user-agent and reverse-DNS.

Showing 24 of 507 ranges

Block or allow MJ12bot/v1.4.8

Block it

Add a Disallow rule for Mozilla/5.0 (compatible; MJ12bot/v1.4.8; http://mj12bot.com/) in your robots.txt file. You can also block at the server level using your web server configuration or CDN firewall rules to filter requests matching the user-agent string.

# Block MJ12bot/v1.4.8 from crawling your entire site
User-agent: Mozilla/5.0 (compatible; MJ12bot/v1.4.8; http://mj12bot.com/)
Disallow: /

# Allow MJ12bot/v1.4.8 full access
User-agent: Mozilla/5.0 (compatible; MJ12bot/v1.4.8; http://mj12bot.com/)
Allow: /
Allow & verify

Ensure your robots.txt allows Mozilla/5.0 (compatible; MJ12bot/v1.4.8; http://mj12bot.com/). Verify requests by checking the user-agent string.

Traffic & trends

Cloudflare Radar traffic

No Cloudflare traffic data available.

Google Trends interest

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Related bots

Other crawlers operated by Majestic-12 Ltd.

Data sources

This profile is compiled from the following sources.

CrawlersDatabase
Last updated September 22, 2026

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