What are the Different Types of Web Crawlers?
7 minutes reading
Your website is constantly under surveillance. Of course, there are your regulars. Humans who visit to look around, interact, and occasionally buy your products. And then there are various types of web crawlers.
Most website owners are well aware of what a web crawler is, but not all realize that there are several types of these bots lurking on their website, doing their job.
Indeed, while your human visitors are pretty chaotic in their behavior (though marketers find patterns they exploit), web crawlers follow strict rules about what to do and what not to do. How web crawlers work actually defines their type, usefulness to your business, and generally whether you should keep them around or chase them away.
To illustrate this better, imagine your website as an airport. Crawlers are like airplanes. They basically have the same function, and, without looking closely, they perform the same task—flying. However, just like some airplanes carry passengers, so do some crawlers bring visitors to your website. There are also cargo planes, security fighter jets, reconnaissance, and even enemy jets.
As you can imagine, trying to land all of these at the same time will create massive chaos, and your airport will be overloaded. Naturally, all operations will shut off, and you will lose passengers, business, and revenue.
That’s why you need a control tower to direct and manage your airspace. Every plane has a purpose, and so does every crawler. To manage them wisely, you must first understand their mission.
So, let’s talk about the different types of web crawlers and how they affect your website and SEO.
Main Categories of Web Crawlers
Knowing who’s landing on your website is the bare minimum. Each bot has its own mission, flight path, and impact on your performance. Some improve visibility and rankings, while others strain your bandwidth or collect data you’d rather keep private. Understanding the main types of web crawlers helps you separate the valuable traffic from the noise and take control of your site’s efficiency.
Search Engine Crawlers
These are the good guys — the passenger planes of your digital airport. Search engine crawlers, such as Googlebot and Bingbot, visit your website to discover, index, and refresh your pages. They follow links, read metadata, and evaluate structure, helping the search engine giants decide where to place you in their search results. Their visits are predictable, regulated by your robots.txt file, and essential for organic visibility. Allowing them to move freely ensures your website stays visible to users searching for your services.
SEO and Marketing Crawlers
SEO crawlers are reconnaissance aircraft. They inspect your website’s structure, backlinks, and technical health to help marketers understand how search engines view your site. Tools like AhrefsBot, SEMrushBot, and Screaming Frog fall into this category. They analyze internal links, site speed, and on-page SEO. While helpful, these crawlers can be resource-intensive, especially for smaller sites with limited hosting power. Allowing them in moderation provides insights without straining your bandwidth.
Social Media and Aggregator Bots
When you share a link on LinkedIn, Facebook, or X, these platforms send their own bots to fetch previews. Facebook External Hit and Twitterbot collect metadata, titles, and images to display attractive snippets on timelines and feeds. They’re like cargo planes that deliver content snippets rather than people. These bots are mostly not a problem, though we’ve seen them temporarily spike your overall resource usage during viral sharing of your web pages.
Commercial and Data Crawlers
These are the business jets of the crawler world. AmazonBot, Common Crawl, and similar bots gather massive amounts of data for research, e-commerce, or AI training. They’re often legitimate but can be resource-intensive. Some perform large-scale scans of the web to improve datasets or compare pricing. If you’re running an online store, too many of these visits can distort analytics or slow down your website. Keeping an eye on them in your crawlerlist helps ensure your data stays accurate.
Malicious or Rogue Crawlers
Then there are the ones that never filed a flight plan. Malicious crawlers scrape content, harvest emails, or attempt brute-force logins. They ignore your robots.txt rules and can flood your server with unnecessary requests. Their presence can distort analytics, inflate bounce rates, and even harm SEO. Blocking or filtering them through firewalls, bot management tools, or advanced hosting configurations is essential for site stability.
Every crawler type plays a role in your website’s ecosystem, whether positive or negative. What matters is how you handle them. The aim is to give the right bots permission to land while blocking those that waste your resources. Proper web crawler management ensures your digital runway remains safe, organized, and efficient. To do this, you need to know a bit more about the most common bots you will find on your website.
Popular Bots and How They Interact With Your Website
By now, you already know the main types of web crawlers, but understanding how specific bots behave helps you spot them faster and assess their impact. Every crawler leaves a signature — its user agent, frequency of visits, and how deeply it explores your site. Some act predictably and helpfully, while others are resource-hungry or even disruptive. Knowing which bots fall into which categories lets you manage your crawlerlist with precision and confidence.
Search Engine Crawlers
| Bot Name | Key Function | Typical Behavior / Interaction | Pros | Cons |
| Googlebot | Indexes your website for Google Search | Obeys robots.txt, crawls regularly, prioritizes mobile-first indexing | Ensures visibility in search results | Heavy crawl frequency on large sites |
| Bingbot | Discovers and updates pages for Bing Search | Follows crawl-delay settings, refreshes cached pages | Expands reach beyond Google | Sometimes slow to reindex new content |
| YandexBot | Indexes content for Russian users | Similar to Bingbot, follows robots.txt | Improves regional SEO | May slow site speed if not rate-limited |
| Baidu Spider | Crawls Chinese-language content | Focuses on .cn and Chinese domains | Access to Baidu search engine | Limited relevance for global sites |
SEO and Marketing Crawlers
| Bot Name | Key Function | Typical Behavior / Interaction | Pros | Cons |
| AhrefsBot | Collects backlinks and SEO data | Crawls aggressively, obeys robots.txt | Helps improve backlink strategy | Can consume bandwidth |
| SEMrushBot | Performs SEO audits and keyword research | Respects crawl rules, scans full structures | Identifies site issues | May increase server requests during audits |
| Screaming Frog | Manual SEO audit tool | Controlled by the user, respects all crawl settings | Ideal for on-demand audits | Limited to local scanning unless licensed |
Social Media and Aggregator Bots
| Bot Name | Key Function | Typical Behavior / Interaction | Pros | Cons |
| Facebook External Hit | Fetches link previews for Facebook shares | Reads Open Graph tags and featured images | Enhances shared link visibility | Can spike traffic during viral sharing |
| Twitterbot | Gathers metadata for X (Twitter) cards | Scans URLs shared on the platform | Helps content look professional on timelines | Limited to metadata collection |
| LinkedInBot | Collects page titles and images for LinkedIn posts | Fetches minimal content | Improves post previews | Short crawling sessions offer little SEO value |
Commercial and Data Crawlers
| Bot Name | Key Function | Typical Behavior / Interaction | Pros | Cons |
| AmazonBot | Gathers product data and page info | Analyzes pricing, content, and availability | Valuable for market visibility | Can duplicate product information |
| Common Crawl | Creates open datasets for AI and research | Massive-scale crawler with public data output | Supports machine learning and research | Extremely heavy server load if unchecked |
Malicious or Rogue Crawlers
| Bot Name / Type | Key Function | Typical Behavior / Interaction | Pros | Cons |
| Scrapers | Copy website content or product listings | Ignore crawl rules and fetch full pages | None | Steal content, harm SEO, and overload servers |
| Spam Bots | Submit fake data or comments | Abuse forms and comment sections | None | Distort analytics, waste bandwidth |
| Credential Stuffers | Attempt brute-force logins | Use automated login requests | None | Serious security threat, can lead to data breaches |
These tables show that even within the same types of web crawlers, behaviors can vary drastically. Some operate transparently and improve your website’s visibility, while others work silently in the background, slowing down performance or consuming resources. Maintaining a clean crawler list and regularly tracking user agents helps you identify patterns and act before they become a problem.
Understanding these specific bots gives you visibility into your traffic quality and control over your digital ecosystem. As you can imagine, this is a necessary foundation for keeping your website stable, secure, and optimized.
Comparing Web Crawler Behavior
As you can see, not all types of web crawlers behave the same once they land on your website. Some are efficient, structured, and respectful of your resources. Others act unpredictably, ignoring your rules and consuming more bandwidth than your actual visitors. Recognizing these differences helps you balance visibility with performance and stop unnecessary traffic before it affects your users.
Think of it as managing your airport’s runway schedule. Commercial flights follow strict air traffic control instructions, while rogue jets appear without clearance, demanding fuel and attention. In the same way, search engine crawlers follow crawl-delay rules, revisit pages when needed, and leave once their tasks are complete. Malicious bots, on the other hand, flood your server with constant requests, often disregarding security protocols and slowing your website down.
How Crawler Types Differ in Purpose and Behavior:
| Crawler Type | Purpose | Crawl Frequency | Follows Rules (robots.txt) | Server Impact | Overall Effect |
| Search Engine Crawlers | Index content for search visibility | Regular and controlled | Always | Low to moderate | Improves SEO and discoverability |
| SEO & Marketing Crawlers | Audit websites and collect performance data | Periodic, tool-based | Usually | Moderate | Provides insights but can strain bandwidth |
| Social Media Bots | Fetch previews for shared links | Occasional | Yes | Low | Enhances link display and engagement |
| Commercial / Data Crawlers | Collect large-scale or research data | Frequent and intensive | Partially | High | Can slow site and distort analytics |
| Malicious or Rogue Crawlers | Scrape or exploit website data | Unpredictable and constant | Never | Very high | Harms performance and security |
As you can see, even crawlers from the same crawlerlist can vary in how often they visit, how much data they take, and whether they respect your crawl rules. Monitoring these patterns helps you anticipate server load and maintain optimal performance.
Understanding how these behaviors differ lays the groundwork for improving your website’s SEO strategy and protecting its stability. Knowing which crawlers bring value and which cause harm lets you optimize your resources and focus your efforts where they matter most.
Why Understanding Different Crawler Types Matters for SEO
Search visibility depends on how efficiently search engines crawl your website. When too many bots visit without control, your server spends time responding to irrelevant requests instead of helping the ones that matter. Understanding the types of web crawlers ensures that your most valuable pages get indexed quickly and your site remains fast for real visitors.
Search Engine Crawlers
Search engine crawlers, such as Googlebot or Bingbot, prioritize sites that load quickly and respond consistently. If your hosting struggles with unnecessary bot traffic, these important crawlers might skip parts of your website or delay re-indexing new content. That’s how websites end up with outdated listings or missing pages in search results. Yes, it’s not due to poor SEO, but rather inefficient bot management.
SEO and Marketing Bots
SEO and marketing bots also play a role in optimization. Tools like AhrefsBot and SEMrushBot review your backlinks, keywords, and internal links to help you strengthen your Backlink portfolio. They analyze how your website connects to others and how authority flows between pages. Having them crawl strategically gives you insight into ranking performance without consuming unnecessary bandwidth.
Malicious Crawlers
However, not all crawlers add value. Overly aggressive data crawlers or scrapers waste resources and distort your analytics. They inflate session numbers and increase server load, leaving fewer resources for genuine users and beneficial crawlers. A healthy crawlerlist helps you filter out this noise, keeping your SEO metrics accurate and reliable.
Knowing which bots help and which harm creates a more efficient crawl ecosystem. When search engines can move freely and other bots stay in check, your crawl budget stretches further, your uptime improves, and your rankings respond faster to updates. Maintaining a clear visitor crawler list lets you fine-tune access, ensure fast indexing, and maintain consistent visibility in search results.
Understanding how these interactions shape SEO naturally leads to the next challenge: identifying who’s visiting and controlling how they behave. That’s where the real value of crawler awareness begins.
How to Identify and Manage Web Crawlers
Knowing the types of web crawlers is only half the work. The real challenge is identifying who’s actually visiting your website and managing their behavior before it affects performance. Without visibility into your traffic, even helpful bots can create issues.
The first step is to learn how to spot them. Every crawler identifies itself with a user agent, a short line of text that tells your server who is making a request. You can find these in your website’s access logs or analytics reports. Legitimate search bots like “Googlebot” or “Bingbot” are clearly listed in the user-agent list. Suspicious crawlers often disguise themselves as browsers or real users. If you notice repeated hits from unknown agents, that is your first clue that something is wrong.
To verify if a crawler is legitimate, perform a quick DNS lookup. Search engine bots always operate from verified domains such as “googlebot.com.” Anything else claiming that name but coming from a different IP is fake. We also suggest using tools like Google Search Console or third-party SEO crawlers to monitor legitimate bot activity. These dashboards show which crawlers accessed your site, when they visited, and how many pages they requested.
Once you know who is visiting, you can control what they do. Your crawlerlist helps track this over time, separating the reliable bots from those that do not follow your rules.
Here is how to keep control:
- Update your robots.txt file. Define which pages crawlers can and cannot access.
- Set crawl-delay parameters. Slow down bots that visit too frequently to reduce server load.
- Use IP blocking or rate limiting. Prevent resource-heavy crawlers from overloading your site.
- Enable a web application firewall (WAF). Stop suspicious or malicious requests before they reach your website.
- Review your analytics regularly. Watch for unusual spikes that could signal unwanted crawler activity.
Managing crawlers effectively protects your resources, keeps your SEO metrics accurate, and maintains site speed for real users. With a clean crawler list, you can welcome the right bots and filter out those that only waste bandwidth.
Building that balance takes ongoing attention, but with a reliable hosting setup, it becomes a smooth, predictable process that strengthens both security and performance.
Stay Crawl-Safe with HostArmada
No matter how well you understand the types of web crawlers, keeping them under control depends on the strength of your hosting foundation. Even the most efficient robots.txt file cannot protect a website if the server struggles with performance or security. Your infrastructure determines how well your site handles both legitimate and unwanted crawler traffic.
Think of HostArmada as the control tower at your online airport. It keeps every flight on schedule, directs the approved ones to land smoothly, and blocks those that arrive without clearance. Fast, secure, and stable hosting ensures that helpful bots like Googlebot can index your pages quickly, while malicious ones are stopped before they cause any damage.
HostArmada’s platform is built for balance and reliability. Resource isolation prevents bad crawlers from affecting your site’s speed. Solid-state drives and optimized caching help search engine bots access your content faster. Advanced firewalls protect against spam crawlers and brute-force attempts. And with consistent uptime and expert support, your website remains open for business to the visitors and bots that matter most.
Just like a well-managed airport, your site performs best when every system works together. Understanding who is landing, why they are there, and how to manage them keeps your online presence efficient, secure, and visible. With the right hosting partner, your website can stay fast, stable, and ready for every crawler that truly deserves to land. So, check out our hosting plans and choose the one that best fits your needs.
