The web contains an unimaginably large amount of data. Unfortunately, most of this data is unstructured and difficult to leverage in a meaningful way. Whether due to the data format used, the limitations of a specific website, or other reasons, there is huge potential to access and structure this data.

This is where web scraping comes in. By automatically extracting and processing unstructured content from the web, you can build impressive datasets that provide deep knowledge and competitive advantage.

However, web scraping is not always that simple and there are many challenges you need to be aware of. In this article, you will learn about the five most common challenges you face when doing web scraping, including IP blocking and CAPTCHA, and how to solve them.

IP Blocking

To prevent abuse and web scraping, websites often implement blocking mechanisms based on client unique identifiers such as IP addresses. On these websites, exceeding set limits or attempting suspicious actions will result in your IP address being banned from accessing the website, effectively blocking automated web scraping.

Websites can also implement so-called geo-blocking (blocking IPs based on detected geographical locations) and other anti-bot measures, such as IP origin or abnormal usage pattern detection, to detect and block IPs.

Solutions

The good news is that there are several ways to solve IP blocking. The simplest approach is to adjust your requests to fit within the limits set by the website, controlling your request rate and usage patterns. Unfortunately, this greatly limits the amount of data you can scrape in a given time.

A more scalable solution is to use a proxy service that implements IP rotation and retries to prevent IP blocking. The best providers, such as PIA S5 Proxy, ensure a high success rate for each request.

That being said, it’s worth noting that using proxies and other blocking circumvention mechanisms for web scraping may be considered unethical. Make sure to follow local and international data regulations, and consult the website’s Terms of Service (TOS) and other policies before proceeding.

CAPTCHA

In addition to IP blocking, CAPTCHA (Completely Automated Turing Test to Tell Computers and Humans Apart) is another popular anti-bot mechanism. CAPTCHA relies on users completing simple tasks to verify that they are human. It is often used to protect areas that are particularly susceptible to spam or abuse, such as registration forms or comment sections, and as a tool to block bot requests.

From images and text to audio and puzzles – CAPTCHAs come in many forms. Beyond that, modern solutions, including Google’s reCAPTCHA v3, implement frictionless bot detection mechanisms based entirely on user interactions with a given website. Dealing with CAPTCHAs is not easy due to the sheer variety of them.

Solution

PIA S5 Proxy, can reliably solve CAPTCHAs and help with successful web scraping.

By leveraging artificial intelligence (AI) and machine learning (ML), Scraping Browser first identifies the type of challenge a CAPTCHA implements, then applies the appropriate solution to solve it. With these modern technologies, Bright Data can guarantee a high success rate, no matter what CAPTCHA you’re facing.

As with proxy services and IP rotation, CAPTCHAs often exist for a reason, and you should follow the website’s TOS and other policies to stay compliant.

Rate Limiting

IP blocking and CAPTCHAs are potential ways to implement rate limiting. In contrast, websites use rate limiting to prevent abuse and various attacks (such as denial of service attacks). When you exceed the limit, your requests are throttled or blocked entirely, using the techniques mentioned earlier.

At its core, rate limiting is about identifying individual clients and monitoring their usage to avoid exceeding the set limit. Identification can be based on IP or use other techniques like browser fingerprinting (e.g. detecting various characteristics of the client to create a unique identifier). Checking the user agent string or cookies can also be part of the identification process.

Solutions

You can avoid rate limits in a number of ways. The simplest way is to control the frequency and timing of your requests to achieve more human-like behavior (e.g. random delays or retries between requests). Other solutions include rotating IP addresses and customizing various attributes like the user agent string and finally browser fingerprinting.

Proxies like PIA S5 Proxy combine all of these solutions and more to provide the best results. With features like IP rotation, browser fingerprinting simulation and automatic retries, you can ensure that you never run into rate limits.

PIA S5 Proxy uses the world's best proxy servers, 350 million real residential IPs worldwide and over 20,000 customer services. Its global proxy network includes:

Residential Proxies - Over 350 million residential IPs in over 200 countries.

ISP Proxies - Over 350 million ISP IPs.

Dynamic Content

In addition to rate limiting and blocking, web scraping involves dealing with other challenges, such as detecting and processing dynamic content.

Today, many websites are more than just plain HTML. They contain a lot of JavaScript, not only for adding interactivity, but also for rendering UI parts, additional content, and even entire pages.

Single-page applications (SPAs) rely on JavaScript to render almost every website part, while other types of web applications use JavaScript to load content asynchronously without refreshing or reloading the page, so that features such as infinite scrolling can be easily implemented. In this case, processing HTML alone is not enough.

Solution

In order to display dynamic content, you have to load and process JavaScript code. This is difficult to implement correctly in custom scripts. This is why using headless browsers and web automation tools such as Playwright, Puppeteer, and Selenium is often more popular.

PIA S5 Proxy provides a dedicated API that you can connect with your favorite web automation tool. This way, you get all the benefits of the PIA S5 Proxy platform - including proxying and unblocking capabilities - as well as the extensible web scraper of a headless browser. This ensures that you can easily scrape even those websites that rely heavily on dynamic content.

Page Structure Changes

Another challenge you may face when doing web crawling is changes in page structure. Your web crawler parser is probably built on a set of assumptions about the structure of the website in order to extract the content you need. However, this also means that any changes in structure will invalidate your parser.

Websites can change their structure without the web crawler taking it into account. Often, this is to optimize the website or to do a redesign. From the web crawler's perspective, there is no way to know when the page structure will change again. This means that the key to dealing with these changes is to create more resilient and versatile parsers.

Solution

To deal with changes in the page structure of your website, make sure your parsers rely as little as possible on the page structure. They should rely mainly on key elements that are least likely to change, and use regular expressions or even AI to rely on the actual content rather than its structure. Also, make sure to account for structural changes and other potential errors to make your parser more resilient. And log these errors and update the parser as needed.

You can also consider implementing a monitoring system with a set of automated tests. This way, you can reliably check changes in the website structure and make sure it matches your expectations. If not, a connected notification system can keep you updated, ensuring that you can take action and update your scripts as soon as the website changes.

Consider using the PIA S5 Proxy API. It allows you to efficiently scrape data for dozens of popular domains and has built-in access to PIA S5 Proxy's powerful infrastructure.

When you scrape the web, you'll face a variety of challenges that vary greatly in terms of impact and the effort required to overcome them. Fortunately, for the vast majority of these challenges, solutions already exist. The PIA S5 Proxy platform is a great example of a platform that provides you with a complete toolset to easily solve the five major issues you've learned about here.

When you scrape the web, make sure to comply with applicable data regulations, the website's TOS and other data policies, and special files like robots.txt. This helps you stay compliant and respect the website's policies.

If you find that the challenges you face are too difficult to overcome on your own, PIA S5 Proxy also offers the latest datasets for you to use. You can use one of their pre-built datasets or request a customized dataset that meets your needs.

Talk to a data expert at PIA S5 Proxy to find the right solution for you.

PIA S5 Proxy has always been committed to providing quality products and technology, and constantly improving price competitiveness and service levels to meet your needs. If you have any questions, please feel free to contact our sales consultants. If you find this article helpful, please recommend it to your friends or colleagues.