Search Engine Optimization (SEO) web crawler bots play a key role in digital marketing through their interactions with web pages. They are responsible for crawling and indexing web pages to retrieve and pick up data, generally to add to their index for usage in SEO tools and software.
These bots are important because the crawling from these site-monitoring bots is what provides us with the necessary data that allows us to analyze search engine performance. These crawlers highlight both the opportunities for organic traffic growth and issues in need of addressing.
However, not all web crawler bot traffic is good for your website. Many issues can potentially arise, especially for the bots that are more aggressive in their crawling. These include resource consumption, data security and privacy concerns, and control over content access.
There are many different versions of web crawlers, and here we will focus solely on introducing these bots in the context of SEO.
SEO web crawler bots function by crawling websites. This means that they are systematically visiting websites, navigating through the content and links found within the page, and gathering information about them. All of this information is added to their index, which is a database that contains all of this web page data that the crawler has found.
To help you understand this better, think of when you use the search bar on Google. This search gets the results from their index, finding the most relevant options based on the information you provide in the form of a search query. All of this indexing is done with Google’s web crawler, Googlebot.
In the context of search engine optimization, bots such as AhrefsBot and SEMRushBot are deployed to analyze websites for SEO health. When they gather data on a given website, they look into factors such as backlinks, keyword density and the structure of the website. They can also detect issues such as a slow load speeds, broken links, duplicate content, and many more.
AhrefsBot is a web crawler that collects and compiles the data necessary to power Ahref’s all-in-one SEO software and Yep, their revenue-sharing search engine platform. The data collected from this bot is used within their tools for keyword research, site auditing, and backlink analysis.
According to a statement made by Ahrefs, this bot is the most active SEO bot, and the third most active of all bots, not far behind Google and Bing. This bot visits more than 8 billion websites everyday to continuously update its database throughout the day. These updates are completed multiple times an hour, and it is how they achieve accurate, up-to-date analysis on each website.
More Information - https://ahrefs.com/robot
MJ12bot is a web crawler that comes from Majestic’s set of SEO tools. The focus of Majestic's software services are a specialization in the backlink profile analysis of websites.
The data retrieved from their crawler allows them to provide SEO analysis, including their own metrics for assessing how trustworthy and influential a website is based on their backlinks. They also help us understand how different pages are interconnected through both internal and external links.
Majestic also scrapes the web with this bot with the intention of building a powerful search engine with a downloadable crawler that enables others to contribute. This project remains in the research phase at the time of this article.
More information - https://www.mj12bot.com/
SemrushBot is the web crawler operated by SEMRush, a company offering a platform with complete SEO and content marketing tools.
This bot is responsible for obtaining the data that allows SEMRush to provide detailed analytics that is offered in their software. These include their Backlink Analytics, their Site Audit tool, Backlink Audit tool, and many more. Find out more about what their data is used for here.
When SEMRushBot crawls a website, it begins with a list of different websites. As the crawler visits these pages, it keeps the links within the page for future crawling, and these are used for future crawling to look for updates.
More information - https://www.semrush.com/bot/
Dotbot is a web crawler from Moz, another software company providing strong SEO solutions with an all-in-one toolset. Their products focus on site audits, rank tracking, backlink analysis, keyword research and more. Learn more here.
This web crawler scrapes web pages in order to accumulate data for the Moz Link Index, and this powers Moz Pro Campaign’s Links section, their Link Explorer tool, and their Moz Links API.
More information - https://moz.com/help/moz-procedures/crawlers/dotbot
Rogerbot is another web crawler from Moz but is their site audit crawler that focuses on gathering data for Moz Pro Campaigns, which is their process of tracking a site with competitor websites. When used, it is regularly updated in order to gather SEO insights for your use.
It allows users of Moz Pro to implement SEO strategies by finding opportunities with their backlink profile, as well as locating any issues with their content that could affect the site’s SEO. Other possibilities include gathering and analyzing keywords and building reports to share with colleagues.
More information - https://moz.com/help/moz-procedures/crawlers/rogerbot
Screaming Frog SEO Spider is a program used by SEO professionals and agencies for SEO site auditing services. The bot is designed to crawl any number of provided websites in real-time to gather data to make educated decisions on a given website(s).
The main distinguishing factor that makes this bot stand out is that it is a tool used by professionals for analysis on their own websites. Similar to how search engine bots would crawl a website, it finds data on SEO aspects such as analyzing page titles, meta data, meta robots and directives, and many more.
More information - https://www.screamingfrog.co.uk/seo-spider/.
CognitiveSEO offers a SEO software solution that allows users to conduct backlink analysis, research keywords, audit sites and track ranking. Their bot collects data in order to power their analytics on performance and evaluation of website ranking.
More information - https://cognitiveseo.com/blog/3212/im-bot-james-bot/
Last but not least, OnCrawl is a technical SEO data provider that provides detailed analytics for websites. Their bot scans websites and analyzes the elements within so that they are able to provide an assessment and report for the SEO professional.
With so many active web crawling bots out there, you may be asking, why block SEO bots? There are several reasons why:
Depending on the bot, their crawl rate can be quite resource-intensive. This can result in your website performance slowing down, greatly impacting user experience. When you block these SEO bots, you can prevent some of these bots from consuming your server resources.
SEO bots are continuously crawling your content in order to collect data, and this can include information that is both personal and sensitive.
For example, there is the potential for some bots to collect data on website visitors. With this data in their hands, they can become targets of cyber attacks. If this data is breached, it can greatly impact both the users and the website.
As bots are continuously visiting your website, this can have an impact on your website traffic analytics. Bot access results in inaccuracy of visitor clicks and data, and can make it hard to understand the difference between organic traffic and clicks by a person versus bot traffic.
Not a lot of steps are required to block these bots, and the simplest method is within the robots.txt file of your given website.
To see the most updated version for any website, it can be accessed by adding /robots.txt to the end of the subdomain of a website.
For Originality.ai, this would look like:
Each bot identifies themself as a user-agent, and can be either blocked completely or partially blocked. For complete blockage, add the following to your robots.txt files for the given bots:
User-agent: Screaming Frog SEO Spider
If you only want to block off certain areas of you website, you can do it like so:
User-agent: Example Bot
Disallow: /example-link, /example-link-2
Take a look at this example:
Taken from Google’s robot.txt file, this informs all robots (indicated by the asterisk) not to access the parts of the website that are found within the ‘/search’ path.
Search engine crawlers are everywhere, and the usage of this technology can be a powerful tool to provide valuable insight for SEO professionals and users. These tools can help boost search engine optimization for websites and increase organic traffic by analyzing your website's content and finding relevant keywords.
However, It is important to understand what each SEO bot does when they are visiting your websites. It is clear that there are potential downsides to allowing bot traffic to your websites, especially with those with a higher crawl rate. With this understanding, you can decide whether or not to add these SEO bots to your robots.txt files.
Hopefully, this article was helpful. If there are any questions, please do not hesitate to reach out by email and contact us.