The web contains unfathomable amounts of data. Unfortunately, most of that data is unstructured and difficult to leverage in a meaningful way. Whether that’s because of the data format used, the limitations of a given website, or something else, there’s no denying that accessing and structuring this data can have immense potential.
That’s where web scraping comes in. By automating the extraction and processing of unstructured content from the web, you can build impressive data sets that provide you with in-depth knowledge and a competitive advantage.
However, web scraping isn’t always straightforward, and there are quite a few challenges you need to be aware of. In this article, you’ll learn about five of the most common challenges you’ll face when web scraping, including IP blocking and CAPTCHA, and how to solve these issues.
To prevent abuse and web scraping, websites often implement blocking mechanisms that depend on a unique identifier for the given client, such as an IP. On these websites, exceeding set limits or attempting suspicious actions results in your IP being banned from accessing the website, effectively preventing automated web scraping.
Websites can also implement so-called geo-blocking (blocking IPs based on the detected geographical location) and other antibot measures, such as IP origin or unusual usage pattern detection, to detect and block IPs.
The good news is there are several solutions to IP blocking. The simplest one is adjusting your requests to limits set by the website, controlling your request rate and usage patterns. Unfortunately, this severely limits how much 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, like the Bright Data Web Unlocker, include even more features to guarantee a high success rate for every request.
With that said, it’s worth noting that web scraping with the use of proxies and other blocking circumvention mechanisms can be considered unethical. Be sure to follow your local and international data regulations and consult the website’s terms of service (TOS) and other policies before proceeding.
In addition to IP blocking, CAPTCHA, which stands for Completely Automated Public Turing test to tell Computers and Humans Apart, is another popular antibot mechanism. CAPTCHA relies on users completing simple tasks to verify they’re human. It’s often used to protect areas especially sensitive to spam or abuse, such as sign-up forms or comment sections, as well as a tool for blocking bot requests.
From images and text to audio and puzzles—CAPTCHAs take many forms. On top of that, modern solutions, including Google’s reCAPTCHA v3, implement frictionless bot detection mechanisms based entirely on the user’s interaction with the given website. With such variety, it’s not easy to combat CAPTCHAs.
By utilizing artificial intelligence (AI) and machine learning (ML), the Scraping Browser first identifies the type of challenge CAPTCHA implements and then applies the proper solution to solve it. With these modern techniques, Bright Data can guarantee a high success rate, no matter the kind of CAPTCHA you face.
Just like with proxy services and IP rotation, CAPTCHAs are usually there for a reason, and you should follow the website’s TOS and other policies to stay compliant.
IP blocking and CAPTCHA are potential ways of enforcing rate limits. In comparison, websites use rate limiting to protect against abuse and various kinds of attacks (such as denial of service). When you exceed the limit, your requests are throttled or entirely blocked using the previously mentioned techniques.
At its core, rate limiting focuses on identifying a single client and monitoring their usage so as not to exceed set limits. Identification can be IP-based, or it can use other techniques, like browser fingerprinting (ie detecting various features of the client to create a unique identifier). Checking user-agent strings or cookies can also be a part of the identification process.
You can avoid rate limits in various ways. The simplest one involves controlling your request frequency and timing to implement more human-like behaviors (eg random delays or retries between your requests). Other solutions include rotating your IP address and customizing various properties (like user-agent string) and, ultimately, the browser fingerprint.
Proxies like Bright Data’s combine all these solutions and more to provide the best results. With features like IP rotation, browser fingerprint emulation, and automatic retries, you can be sure you’ll never hit rate limits.
Bright Data controls the best proxy servers in the world, serving Fortune 500 companies and over 20,000 customers. Its worldwide proxy network involves:
- Datacenter proxies – Over 770,000 datacenter IPs.
- Residential proxies – Over 72M residential IPs in more than 195 countries.
- ISP proxies – Over 700,000 ISP IPs.
- Mobile proxies – Over 7M mobile IPs.
Apart from rate limiting and blocking, web scraping involves facing other challenges, such as detecting and handling dynamic content.
Bright Data provides a dedicated Scraping Browser API, which you can connect with your favorite web automation tool. With that, you get all the benefits of the Bright Data platform—including proxying and unblocking features—on top of scalable web scraping with headless browsers. This ensures you can easily scrape websites, even those that depend heavily on dynamic content.
Another challenge you might face when web scraping is the changes to the page structure. Your web scraping parsers are likely built on a set of assumptions on how the website is structured. It’s necessary to extract just the content you need. However, it also means that any change to the structure renders your parser obsolete.
Websites can change their structure without much consideration for web scrapers. Usually, it’s done to optimize the website or implement a redesign. From the web scraping perspective, there’s no way to know when the page structure will change again. This means the key to mitigating the effect such changes have on your web scraping is to create more resilient and versatile parsers.
To handle changes in a website’s page structure, make sure your parsers depend on the page structure as little as possible. They should rely primarily on key elements that are least likely to change and use regular expressions or even AI to depend on the actual content rather than its structure. Additionally, be sure to account for changes in the structure and other potential errors in order to make parsers more resilient. And keep a log of these errors and update your parsers as needed.
You can also consider implementing a monitoring system with a set of automated tests. This way, you can reliably check for changes in the website’s structure and make sure it aligns with your expectations. If it doesn’t, a connected notification system can keep you in the loop, making sure you can take action and update your scripts as soon as the website changes.
To build great parsers, you can use the Bright Data Web Scraper IDE. It allows you to prototype and debug your parsers quickly with built-in access to the Bright Data infrastructure with premade templates for you to easily get started with.
When web scraping, you’ll face all kinds of challenges, and they’ll differ vastly in terms of their impact and the effort required to overcome them. Thankfully, for the vast majority of these challenges, there are solutions available. The Bright Data platform serves as a great example, providing you with a full toolset to easily solve the five major issues you learned about here.
When web scraping, be sure to respect the applicable data regulations, the website’s TOS, and other data policies, as well as special files like
robots.txt. This helps you stay compliant and respectful of the website’s policies.
If you find yourself facing a challenge too difficult for you to overcome on your own, Bright Data also provides up-to-date datasets, ready for you to use. You can use one of their prebuilt datasets or request a custom one tailored to your needs.
Talk to one of Bright Data’s data expert to find the right soution for you.