We all know that content is king, but it takes much more than good content to stay ahead of the competition in this dynamic and cluttered world of search engine optimization (SEO).
One of the major aspects that influence the positioning of your content is the role of web crawlers. Web crawlers are the bots who visit your website and play a major role in indexing and ranking your content on the search engine. We need to realize the significance of maintaining a good crawler list.
In this detailed article, we will discuss everything you need to know about web crawlers, including their types, functions, and significance. We will also provide a list of the top 15 web crawlers to boost your SEO efforts.
What are Web Crawlers?
Web crawlers are a type of computer bots, which browse the web and visit websites in an automated manner. They crawl over your content to read the pages and other information, this helps them gather data for a search engine’s index.
Crawlers are also popular with names like ants, robots, or spiders. The main function of a web crawler is to provide a complete and updated index of all the user content. Additionally, they can also help you with other tasks like obtaining contact details and pricing data from the website.
Your SEO rankings are decided by multiple factors like relevancy, backlinks, web hosting, and more. However, it would be of no use, if your web pages were not being crawled or indexed. Thus, an effective crawler list can help businesses manage and optimize their online presence with the help of up-to-date SEO.
Overall, a web crawler offers you multiple functions. Here are some of the major features of a good crawler:
- The main function of a web crawler is to read the content and assist search engines like Google, Yahoo, and Bing in creating and updating the search indexes.
- Few organizations also use crawlers for web archiving, they use them to archive snapshots of websites.
- Data mining is another great feature, you can use these web crawlers to gather data from websites. This feature is beneficial for analysis or research.
- Crawlers also play an important role in checking broken links, monitoring performance, and making sure that the content is updated.
Apart from these functions, a crawler can also be used as a content aggregator to collect information from multiple sources.
Different Types of Web Crawlers
An effective crawler list can be classified into 3 major categories. Let’s discuss and understand these categories before listing the top web crawlers.
In-House Web Crawlers
These types of crawlers are created by organizations themselves to explore their websites. These internal crawlers can assist in creating sitemaps and checking for broken links on the website. Googlebot and Bingbot are the most famous in-house crawlers.
Commercial Web Crawlers
Commercial crawlers are available in the market for purchase. These tools are usually developed by major companies with specialization and experience in such software programs. You can also opt for a customized web crawler design for the unique requirements of your website. AhrefsBot and SemrushBot come under this category.
Open Source Web Crawlers
These crawlers are easily available to the public under free or open licenses. They allow you to use them as per your requirements. They do not provide advanced features like commercial crawlers, but you get into the source code and understand the mechanics of crawling. Apache Nutch and Scrapy are the top open-source crawlers.
So, these are the 3 primary classifications of web crawlers. Moving on, let’s discuss the top 15 crawlers available in the market.
Top 15 Web Crawlers to Include in Your Crawler list
Understanding and optimizing the list of crawler user agents is crucial to make sure that your website is accessible to the target audience. It is important to include the most reliable bots in your crawling list, here are the 15 best crawlers you should consider.
1. Googlebot
Google is the largest search engine in the world, it uses Googlebot crawler to index billions of pages and rank them after analyzing. It is one of the most influential bots in this crawler list for SEO professionals.
Googlebot desktop crawler imitates a person’s browsing on a computer, while Googlebot mobile does the same task for an Android or iOS device. Both of the crawlers except the same user agent token in robots.txt. You can also use robots.txt to selectively target a crawler.
It is a great web crawler, which can do the work quickly and accurately. However, it has some drawbacks too, it does not always crawl all the pages in real time. This means that it may not index some pages even after a few weeks of publishing.
| User Agent | Googlebot |
| Full User Agent String | Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html) |
Google has many web crawlers other than Google’s web search crawler. Let’s take a brief look at some major crawlers:
| Web Crawler | User Agent String |
| Googlebot News | Googlebot-News |
| Googlebot Images | Googlebot-Image/1.0 |
| Googlebot Video | Googlebot-Video/1.0 |
| Google Smartphone | Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.96 Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html) |
| Google Mobile Adsense | compatible; Mediapartners-Google/2.1; +http://www.google.com/bot.html |
| Google Mobile (featured phone) | SAMSUNG-SGH-E250/1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 UP.Browser/6.2.3.3.c.1.101 (GUI) MMP/2.0 (compatible; Googlebot-Mobile/2.1; +http://www.google.com/bot.html) |
| Google Adsense | Mediapartners-Google |
| Google app crawler (fetch resources for mobile) | AdsBot-Google-Mobile-Apps |
| Google AdsBot (PPC landing page quality) | AdsBot-Google (+http://www.google.com/adsbot.html) |
2. Bingbot
Bingbot was developed by Microsoft in 2010 to crawl over the Bing search engine. It is the successor of the MSN bot.
One of the best features of Bing is a tool called Fetch as Bingbot, which enables you to request a web crawler to analyze the page and show the results as seen by a crawler. These powerful insights will help you understand whether the crawlers see your page as you want.
| User Agent | Bingbot |
| Full User Agent String | Mozilla/5.0 (compatible; Bingbot/2.0; +http://www.bing.com/bingbot.htm) |
3. Yandex Bot
Yandex Bot is the web crawler of Yandex. Yandex is a very famous search engine in Russia, Kazakhstan, Belarus, Turkey, and countries with a large Russian-speaking population. Yandex bot is very efficient in indexing web pages and providing relevant search results. It is an important crawler for websites looking to target the Russian audience.
| User Agent | YandexBot |
| Full User Agent String | Mozilla/5.0 (compatible; YandexBot/3.0; +http://yandex.com/bots) |
4. Baidu Spider
The official name of the Chinese Baidu search engine’s web-crawling bot is Baidu Spider. It effectively crawls over all the web pages to update the index and rankings in the Baidu search engine. Baidu is the market leader in China, taking over 80% of the search engine market. Thus, the Baidu Spider is crucial for reaching the Chinese audience.
| User Agent | Baiduspider |
| Full User Agent String | Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html) |
Baidu has 6 additional web crawlers for different needs. Let’s take a brief look at them:
| Web Crawler | User Agent String |
| Image Search | Baiduspider-image |
| Video Search | Baiduspider-video |
| News Search | Baiduspider-news |
| Baidu Wish Lists | Baiduspider-favo |
| Baidu Union | Baiduspider-cpro |
| Business Search | Baiduspider-ads |
5. DuckDuckBot
DuckDuckBot is the crawler or Web spider for DuckDuckGo. It is a conservative search engine for safe browsing that has been quite popular since people are aware that it is privacy-friendly and does not track users. It works continuously to improve the search results and offer a secure experience to the users. This is one of the most secured bots on the crawler list.
| User Agent | DuckDuckBot |
| Full User Agent String | DuckDuckBot/1.0; (+http://duckduckgo.com/duckduckbot.html) |
6. Facebook External Hit
The primary function of the Facebook External Hit is to crawl over the content of a website or an app shared on Meta platforms, such as Instagram, Facebook, or Messenger. This web crawler gathers and displays information like the title and description of the web page.
| User Agent | Facebook External Hit, Facebook Crawler |
| Full User Agent String | facebookexternalhit/1.1 (+http://www.facebook.com/externalhit_uatext.php) |
7. Apple Bot
Apple Bot was developed for crawling and indexing webpages appearing on Apple’s Siri and Spotlight suggestions. This bot takes into account different factors before selecting the content to display on Siri and Spotlight suggestions. User engagement, relevance of keywords, quantity, and quality of links, location, and webpage design are some of the factors responsible for rankings.
| User Agent | Applebot |
| Full User Agent String | Mozilla/5.0 (Device; OS_version) AppleWebKit/WebKit_version (KHTML, like Gecko) Version/Safari_version Safari/WebKit_version (Applebot/Applebot_version) |
8. Slurp Bot
Slurp Bot is the official Yahoo search robot to crawl and index web pages. Many Yahoo search results come from the data of Bingbot, as the Yahoo search engine is also powered by Bing. All the websites should allow access to Slurp to appear in the search results.
Additionally, the Slurp Bot also gathers information from partner sites like Yahoo Finance, Yahoo News, and Yahoo Sports.
| User Agent | Slurp |
| Full User Agent String | Mozilla/5.0 (compatible; Yahoo! Slurp; http://help.yahoo.com/help/us/ysearch/slurp) |
9. Exabot
Exabot is a web crawler used by a search platform company, Exalead (HQ: Paris, France). Exalead offers search results for consumer and enterprise clients.
Exabot crawls over the content and develops a main index to rank the web pages. Similar to any other search engine, it considers both backlinking and the quality of the content before ranking a web page.
| User Agent | Exabot |
| Full User Agent String | Mozilla/5.0 (compatible; Konqueror/3.5; Linux) KHTML/3.5.5 (like Gecko) (Exabot-Thumbnails)Mozilla/5.0 (compatible; Exabot/3.0; +http://www.exabot.com/go/robot) |
10. Swiftbot
Swiftbot is one of the most effective web crawlers on the list. It is a versatile bot developed to gather data for various applications, such as market research, data aggregation, and competitive analysis.
Swiftbot performs efficient scans and quickly indexes web pages for Swiftype. This allows businesses to gain updated information and important insights about the SEO factors of the web page.
| User Agent | Swiftbot |
| Full User Agent String | Mozilla/5.0 (compatible; Swiftbot/1.0; +http://swiftbot.com) |
11. AhrefsBot
AhrefsBot is one of the most advanced commercial web crawlers on the list. This bot crawls over the content of Ahrefs (an online data platform) and Yep (a revenue-sharing web search engine).
It is visiting over 8 billion web pages daily and updating its ranking every 15–30 minutes, making it the 3rd most active web crawler after Google and Bing. Just like other crawlers, it follows robot.txt functions and gives you the power to allow or disallow rules in the code.
| User Agent | AhrefsBot |
| Full User Agent String | Mozilla/5.0 (compatible; AhrefsBot/7.0; +http://ahrefs.com/robot/) |
12. SemrushBot
If you are reading this SEO-heavy article, we don’t need to tell you about Semrush. SemrushBot allows this leading SEO platform to collect and index data for its customers. Semrush’s backlink search engine, site audit tool, backlink audit tool, link building tool, and other tools use the data collected by SemrushBot.
| User Agent | SemrushBot |
| Full User Agent String | Mozilla/5.0 (compatible; SemrushBot/7~bl; +http://www.semrush.com/bot.html) |
13. Sogou Spider
Sogou is another leading search engine in China. It is developed by the Chinese internet company, Sohu. Sogou web spider is a search engine crawler that indexes web pages and collects important data to improve the search results. This bot primarily focuses on ranking the Chinese language websites and pages.
| User Agent | Sogou spider |
| Full User Agent String | Sogou web spider/4.0 (+http://www.sogou.com/docs/help/webmasters.htm#07) (for Sogou Spider Desktop:) |
14. CCBot
CCBot is developed by Common Crawl, a non-profit organization working on providing free access to the internet. It is a Nutch-based crawler that makes use of MapReduce to convert large data into valuable and precise form.
With the help of CCBot, you can use the data provided by Common Crawl. It will help you to improve language translation software and predict trends.
| User Agent | CCBot |
| Full User Agent String | CCBot/2.0 (https://commoncrawl.org/faq/)CCBot/2.0CCBot/2.0 (http://commoncrawl.org/faq/) |
15. Majestic-12
Majestic is a platform that focuses on tracking and identifying backlinks. Majestic-12 is the web crawler associated with Majestic, enabling you to review the backlink data of your web page.
Majestic has one of the most comprehensive sources of backlink data. You can make use of this data with the help of the Majestic-12 web crawler.
| User Agent | MJ12bot |
| Full User Agent String | Mozilla/5.0 (compatible; MJ12bot/v1.4.8; http://majestic12.co.uk/bot.php?+) Mozilla/5.0 (compatible; MJ12bot/v2.0.0; http://majestic12.co.uk/bot.php?+) |
Finally, we have provided you with a detailed crawler list. It covers all the major web crawlers available in the market along with their user agent and full user agent string information.
How to Manage and Optimize Your Crawler list?
After learning about the top web crawlers, it is important to research and create an effective crawler list as per the needs of your website and organization.
- The first step is to identify the most relevant web crawlers for your industry.
- Next, you should use the robot.txt file to manage and customize the access to your website.
- You should regularly monitor your website traffic to identify any new or bad bots. Updating your crawler list to avoid bad bots and include good bots is essential.
- Adjusting the crawl rate is another important aspect. It makes sure that web crawlers do not overload your server and slow down your website.
Furthermore, using tools like Google Search Console and Semrush can assist you in gaining insights into the behavior of web crawlers on your website.
Why is a Crawler List Important for SEO?
If you are still not convinced that web crawlers play a significant role in boosting your SEO rankings, let’s quickly discuss the benefits of maintaining a good crawler list.
- Managing and optimizing web crawlers prevents server overload and website downtime, improving the overall user experience.
- Web crawlers ensure that your content is accurately represented in different search results. This helps in improving the search engine rankings.
- Effective use of bots can also minimize the duplication of content. Duplicate is one of the main villains of SEO performance.
- Excluding bad bots from the crawler list protects your website from cybersecurity risks like data theft.
By understanding and managing the crawlers that visit your site, you can better optimize your content and overall SEO strategy.
Conclusion
This is not an exhaustive list of web crawlers, as there are hundreds of different crawlers. But the good part is that you are now aware of the most popular and effective ones.
From Googlebot to SemrushBot, every web crawler has a different goal for indexing, crawling, ranking, and other related or extended functions. It is important to know their features and learn how to make the best use of different bots in your crawler list to improve your overall strategy and become one of the top SEO experts.
We hope you find this detailed article helpful in implementing the role of web crawlers in your SEO journey.
Which is the best web crawler?
For indexing web pages, Googlebot is the best one. While AhrefsBot and SemrushBot are two of the best in SEO analysis.
How to optimize a web crawler?
To optimize your web crawler, set rules in robots.txt, secure the servers from overload, and optimize crawl rates. Tools like Cloudflare can also help you with the security and performance.
How to check a crawler?
A crawler can be verified by looking at its user-agent string, which identifies the bot and its function.
How Does a Web Crawler Work?
A web crawler starts by following links from previously indexed pages or by starting with a list of seed URLs. After that, it downloads web pages and indexes their content. This process allows search engines to generate a searchable index of the web.
What is crawler activity?
Data collection for indexing or analysis, as well as website access and link following, are all examples of crawler activity.
