Introduction To Web Scraping Without Getting Blocked
Companies of all sizes rely on data for optimized operations. Therefore, web data extraction has become an increasing phenomenon. Scrapers, spiders, or crawlers are instrumental in collecting data from websites quickly and in a structured format.
Search engines like Google, Yahoo, and others need to crawl available websites so they can display relevant information in response to queries. On the other hand, ecommerce businesses need access to data for various purposes, including price monitoring, competitor monitoring, lead generation, sentiment analysis, and more.
Despite the significance of scrapers and crawlers, they are still bots, and their activities may have devastating effects on a website. As a result many websites have taken active steps to prevent any unfortunate incidents by implementing anti-bot / anti-scraping techniques. However, this guide will explore practical steps to help you avoid blocks in your scraping endeavors.
How to Crawl a Website Without Getting Blocked
Web crawling is an essential technique for data extraction, enabling businesses and researchers to gather information from various websites. However, many websites implement measures to detect and block automated bots to protect their data and server resources. To crawl a website effectively without getting blocked, consider the following strategies:
- Respect the Robots.txt File: Before initiating any crawling activities, examine the website’s
robots.txt
file. This file outlines the site’s crawling policies, specifying which areas are off-limits to bots. Adhering to these guidelines demonstrates respect for the website’s preferences and reduces the risk of being blocked. - Implement Rate Limiting: Avoid overwhelming the target server by controlling the frequency of your requests. Introduce delays between successive requests to mimic human browsing behavior. This approach helps prevent detection and ensures the server isn’t overloaded.
- Rotate IP Addresses: Utilizing a single IP address for multiple requests can lead to detection and subsequent blocking. Employ a pool of IP addresses and rotate them periodically to distribute your requests, making it harder for the server to identify and block your crawler.
- Use Realistic User Agents: The User-Agent string in your HTTP headers identifies the browser and operating system of the requester. Customize this string to reflect common browsers and devices, making your requests appear more legitimate.
- Handle Cookies and Sessions Appropriately: Some websites track user sessions through cookies. Ensure your crawler can manage cookies effectively, maintaining session continuity and reducing the likelihood of detection.
- Monitor for CAPTCHAs: Websites may deploy CAPTCHAs to differentiate between bots and human users. Implement mechanisms to detect when a CAPTCHA is presented and develop strategies to handle or bypass them responsibly.
- Avoid Scraping During Peak Hours: Crawling during a website’s peak traffic times can strain its resources and increase the chances of detection. Schedule your crawling activities during off-peak hours to minimize impact and reduce the risk of being blocked.
- Stay Informed About Website Changes: Websites frequently update their structures and anti-bot measures. Regularly monitor the target site for changes and adjust your crawling strategy accordingly to maintain effectiveness and compliance.
By implementing these best practices, you can conduct web crawling activities more effectively while minimizing the risk of being detected and blocked.
Here are some additional practical tips for crawling a website without getting blocked:
Use proxy servers
Web crawling and web scraping would not be efficient without proxies. Therefore, it becomes necessary to choose a reliable proxy provider. A proxy acts as an intermediary between your device and the target website. In other words, it hides your actual IP address, which makes it harder to generate a browser fingerprint.
Premium proxies offer anonymity, security, and privacy from cyber threats. When you send a request to a website, it interacts with your IP address. Subsequently, it can determine your location, which can determine the response you will receive. For example, if you reside in the Philippines and need to access a website that is only available to those in the United States, all you need to do is configure your proxy location for the US. As a result, you have used the proxy to bypass geographic restrictions. Consequently, you can retrieve data from any part of the world without any unnecessary limitations.
Furthermore, for best results, choose a provider with a large IP pool so you can conveniently retrieve web data from various locations. Other factors to consider when choosing a proxy server include:
- Reputation through comments and reviews
- Transparent pricing modes
- The type of proxy server offered
- Degree of anonymity
- Compatibility with various operating systems
- Advanced features like CAPTCHA solving
Rotate IP address
To maximize the benefits of proxies, you need to rotate your IP address. The concept of IP rotation is changing the IP address based on pre-defined parameters. One of the practices that could trigger an IP ban is sending too many requests within a short period from the same IP address. Therefore, you can maintain the integrity of the IP pool by avoiding IP blocks.
Subsequently, proxy rotation significantly reduces the chances of being blocked as the target website sees you as multiple users.
Use real user agent
One of the things that can cause an interruption in data scraping is leaving the user agent empty or using incorrect details. Many servers that host websites often analyze the headers of the HTTP request. User agent can also be called the HTTP request header and it contains several information including the operating system, browser version, and operating systems.
Subsequently, these servers can easily detect suspicious IPs. Since the user agent contains regular HTTP request configurations submitted by organic visitors, you can avoid an IP block by modifying your user agent to mimic an organic one.
In addition, the user agent includes identifying data which is necessary for web pages to load correctly. However, this is not necessary for a web scraper so many people do not remember to set it up. Using an out-dated user agent can trigger the website anti-bot algorithms which results in IP block.
You can work around the user agent issue by setting your user agent string to a popular browser like Chrome. Alternatively, you can use GoogleBot’s User Agent data which is acceptable by many websites as they want to be crawled by Google to rank high in search engine result page.
However, you must remember to rotate the user agent details since the user agent is consistent with every request. In addition, it is crucial to use updated and common user agents.
Be wary of honeypot traps
Honeypots are traps set up by websites to detect and block scrapers. They are links within the HTML codes that are invisible to organic users. However, these links are designed to attract bots that visit the website. Subsequently, honeypots are the perfect traps for web crawlers and scrapers because only bots will follow the link. These links often contain fake information, and their primary aim is to confuse web scrapers and spiders.
So, how can you deal with these seemingly perfect traps? Remember that we mentioned that these links are only visible bots. Therefore, you can include a code that allows your scraper or spider to identify links with CSS properties, which makes them invisible. Subsequently, the scraper should not follow links that were initially hidden or have the same color as the background.
Alternatively, you can avoid the honeypot by respecting the robots.txt file. This instruction in this file is for bots indicating the parts of the website that can be scraped, likewise, those that must be avoided. In addition, honeypots are designed with a tracking system for fingerprinting automated requests for IP bans.
Review the robots.txt file
One of the most critical tips for scraping or crawling a website is to check the robots.txt file. When you review this file, you can safely navigate and respect the rules of the website. Subsequently, you can understand the legal and ethical boundaries provided by the website.
Although the web page may permit scraping, you need to follow the rules indicated in the robot exclusion protocol. Some of these rules include scraping at off-peak hours, limiting requests from an IP address, and implementing a delay timer in sending requests.
Bear in mind that even if the target server allows the scraping of publicly available data, there is still a risk of IP bans. Your IP address may be banned if your scraping activities are perceived as unethical. Therefore, checking the robots.txt is necessary to avoid practices that may trigger the website’s anti-bot measures.
Use CAPTCHA solvers
One of the primary web crawling challenges is CAPTCHAs. These are tests designed to tell humans apart from bots. Subsequently, the text can come in various formats. The common ones include completing a puzzle, selecting the image that matches the one provided, and writing a text from a distorted frame. These tests are often not a problem for humans, but they are designed to be nearly impossible for computers to read.
You can read a recent guide here on how to bypass CAPTCHA with playwright. To handle CAPTCHAs, you need a tool designed to handle them. For example, NetNut proxies come with smart CAPTCHA technology that allows you to bypass them with ease. In addition, our Scraper API is designed to allow customization such that it takes care of CAPTCHA techniques on the target website.
Headless browsers
A headless browser is similar to a regular browser, with the exception of a graphical user interface. Headless browsing mode is supported by Chromium-based browsers like Google Chrome as well as Firefox. Some websites have advanced anti-bot technology that goes beyond checking the IP address and HTTP header. They check other data like fonts, cookies, and extensions to determine the authenticity of the sender.
Subsequently, using a headless browsers significantly reduces the chances of being identified as a bot. Usually, scraping web pages that are heavily reliant on JavaScript is very difficult. However, using headless browsers allows you to render JavaScript content with ease.
Browser automation tools like Selenium allow you to integrate proxies with headless browsers. As a result, your actual IP address is masked, which reduces the chances of getting blocked.
Use NetNut Scraper API
One of the best practices to avoid getting blocked is to use scraper API. These are automated tools that can collect public data without scraping the website. When using a Scraper API, you don’t have to worry about any aspect of the extraction process, including sending the request and unblocking the target.
NetNut Scraper API offers a robust scraping infrastructure that allows you to collect data from SERP, ecommerce, and the web. Once you send the request, the API retrieves it and returns it in a structured format. In addition, you don’t have to worry about geographical restrictions; our API ensures you have access to data from any location you desire. Although getting a scraper API may be more expensive, it saves you a lot of time and effort.
Manage your device fingerprint
Every human being has a unique fingerprint that can be used for identification. In other words, no two individuals, regardless of origin, can have the same fingerprint. Similarly, every device you use to access the internet has its unique fingerprint. Some websites can gather enough data to create a unique fingerprint for your device. As you surf through various websites and platforms, you are leaving a trail of digital crumbs that can be linked to your device parameters like location, browser version, operating system, and more.
Subsequently, modern websites leverage sophisticated ant scraping measures like IP fingerprinting or Transmission Control Protocol to identify automated programs. When you engage in scraping data from the web, the TCP leaves digital crumbs that can be used to track you. Therefore, when you engage in aggressive scrapping, your IP address can easily be blacklisted.
A practical tip is to ensure that your parameters are consistent. Alternatively, you can use NetNut Website Unblocker, which comes with smart fingerprinting functions that ensure you enjoy optimized scraping. The Web Unblocker combines several fingerprinting variables in such a way that it generates the best fingerprint, which is random and bypasses anti-bot measures.
Crawl only during off-peak periods
Another crucial practice to prevent IP blocking is to crawl during off-peak hours. Since a web crawler do not read the content of a page, they move through the pages very quickly. However, this can affect the server’s performance more than any human activity. Therefore, crawling during high-load periods may cause the server to slowdown , which can affect the actual user’s experience.
Subsequently, finding the best time to crawl a website can significantly optimize your scraping efforts. Bear in mind that the off-peak hours vary from one website to another. However, a good place to start is after midnight as the activities of users are significantly lower.
Avoid scraping images
Regardless of the website you are visiting, bear in mind that some data are copyrighted. Scraping copyright data is unethical and can lead to serious legal implications. Examples of copyright materials are images on a website.
Images are resource-intensive, so they demand additional bandwidth and storage space. When you scrape images, there is a high chance that you are infringing on someone else’s rights. In addition, images are often located in JavaScript elements since they are resource-intensive. As a result, this makes scraping or crawling significantly more difficult because the web scraper performance is notably slowed. Getting images from JavaScript elements is a complex process that involves forcing all the content on the website to load.
Use Google cache
Another less-known tip to avoid blocking is to scrape out of Google’s cached copy of the website. This trick is only applicable to websites that do not frequently change their data. In other words, you are not scraping data from the website directly. Instead, you are indirectly collecting the data without putting pressure on the server.
You can achieve this by adding https://webcache.googleusercontent.com/search?q=cache: to the beginning of the URL. For example, if you want to scrape IMDB, you could send the request like this:
https://webcache.googleusercontent.com/search?q=cache: https:// www. IMDB.com
Subsequently, this method is especially useful when the websites are hard to scrape and the data is not time-sensitive. Although scraping Google cache is a bit more reliable and convenient as opposed to websites actively trying to block your IP address.
Common Website Scraping Hurdles That Will Cause You To Be Blocked
When engaging in web scraping, several challenges can lead to your activities being detected and blocked by target websites. Understanding these hurdles is crucial for developing effective strategies to overcome them:
- IP Address Blocking: Repeated requests from a single IP address can trigger security mechanisms, leading to IP bans. To mitigate this, utilize proxy services to rotate IP addresses, distributing requests across multiple sources and reducing the likelihood of detection.
- Detection of Non-Human Behavior: Bots often exhibit patterns that differ from human browsing, such as rapid request rates or accessing pages in a sequential manner. Implementing randomized delays and mimicking human navigation patterns can help your scraper blend in with regular traffic.
- CAPTCHA Challenges: Many websites employ CAPTCHAs to prevent automated access. While solving CAPTCHAs programmatically is complex and may violate terms of service, some services offer CAPTCHA-solving solutions. However, use these responsibly and consider the ethical implications.
- JavaScript Rendering: Modern websites often rely on JavaScript to load content dynamically. Traditional scrapers may miss such content, leading to incomplete data extraction. Utilizing headless browsers or tools that can execute JavaScript ensures that your scraper captures all relevant information.
- Frequent Website Structure Changes: Websites may alter their HTML structure regularly, which can break your scraping logic. Implementing robust parsing methods and maintaining your scraper to adapt to these changes is essential for continued success.
- Session and Cookie Management: Some sites require session management and use cookies to track users. Failing to handle these properly can result in access issues or incomplete data retrieval. Ensure your scraper can manage sessions and cookies effectively to maintain access.
- Legal and Ethical Considerations: Scraping without permission can lead to legal consequences and ethical dilemmas. Always review the website’s terms of service and ensure your activities comply with legal standards and ethical practices.
By recognizing and addressing these common hurdles, you can enhance the effectiveness of your web scraping endeavors while minimizing the risk of being blocked.
Choosing the Best Proxy provider – NetNut
Most limitations regarding web data extraction result in IP blocks. Therefore, it becomes necessary to choose a reliable proxy provider like NetNut that has an extensive network of IPs across multiple locations. Here are the types of proxies you can use for extracting data from online:
Datacenter proxy servers: These servers have IP addresses that originate from datacenters. Although they are the less expensive proxy option, there is a chance of being discovered by sophisticated websites that keep track of IPs from a data center company. With NetNut datacenter proxies, you can enjoy high speed and performance that optimizes your scraping efforts.
Residential proxy servers: Residential proxies are associated with actual physical locations. Therefore, they are more expensive because they have a lesser chance of being blocked. You can opt for static residential proxies if you need to maintain the same IP for a particular session. However, for web scraping, you need rotating residential proxies. NetNut proxies come with automated IP rotation to ensure the highest level of anonymity while bypassing CAPTCHA for optimized scraping activities.
Mobile proxy servers: These proxies use actual mobile IP addresses provided by the ISP. Therefore, your network traffic is routed through mobile proxy servers. These proxies may also be expensive because they are affiliated to actual mobile devices. , NetNut Mobile proxies is a customizable solution that provide security, privacy, and anonymity as you extract data from any website.
In summary, NetNut stands out for its competitive and transparent pricing model. In addition, we guarantee an uptime of 99.9%- we deliver high performance without compromising on quality.
Conclusion
Data has several uses for ecommerce businesses, machine learning, research, and other fields. However, many websites have implemented several strategies, including rate limiting, geographical restrictions, CAPTCHAs, and others, which result in IP blocks. Therefore, it becomes crucial to be able to gather data without fear of being blocked.
The most important thing to guarantee efficiency during web scraping is to use premium proxies. Another thing that you must not overlook is a review of the robots.txt file, which categorically indicates how the website wants to relate to bots.
We hope this guide was informational and relevant in helping you crawl or scrape a website without getting blocked. Do you have any more questions? Feel free to contact us as our customer support is available 24/7 to handle your requests.
Frequently Asked Questions
How do web crawlers work?
Web crawlers are automated programs designed to systematically browse and index web pages on the internet. They play a crucial role in organizing and indexing the wealth of information on the internet to ensure it is available to users. Web crawlers work quite differently from web scrapers. For web crawling, the website owners request search engines to crawl their websites and index their URLs. However, they can specify the parts of the website they do not want to be crawled.
Unless indicated, the web spider determines which websites to crawl. Then it goes through the robot.txt file and crawls accordingly. Subsequently, the spider visits all available URLs, downloads the information, and stores them locally. Information related to meta tags and meta titles are also indexed and stored.
Why do websites use anti-scraping measures?
The primary purpose of anti-scraping measures often implemented by websites is to block data collection. Websites can use anti-scraping strategies for various purposes, including:
- Protection of the website server because if the scraper is not properly designed, it can overload it with requests
- A form of security measure against hackers to ensure only authorized persons can access the data.
- Since some companies sell their data, they may use anti-scraping measures to protect their intellectual property. In addition, anti-scraping prevents unauthorized collection and redistribution of content.
- Websites can implement anti-scraping measures to protect against content theft in this highly competitive market.
- Blocking bots may be necessary to protect customer data and sensitive information.
What form of web scraping is illegal?
Extracting publicly available data is generally permissible on many websites. However, web scraping becomes illegal and unethical when it involves:
- Personal data
- Information protected by login credentials
- Data prohibited by the robot.txt file
- Copyrighted data
- Data categorized by the website as private or off-limit
- Violation of GDPR, CCPA, and CFAA laws