The benefits of web scraping are substantial. It helps you extract an enormous amount of useful information within seconds. Nevertheless, web scraping can be challenging, mainly because of an increasing number of anti-scraping programs implemented by website owners.
Here are some actionable ways to perform web scraping safely without getting blacklisted.
1. Make Your Crawling Slower
Web scrapers are very fast and can fetch tons of data within seconds. But this also makes it easy for a website to detect scraping attempts as humans cannot browse so rapidly. So, if you send a myriad of requests in a small time period, the site will easily determine a bot action and block it.
Therefore, time your scraping adequately to make your crawler look real. You can do it by adding delays after crawling one or two pages or adding sleep calls between two consecutive requests. You can also utilize auto-throttling tools to slow down your crawling speed. In all, try to mimic human browsing action.
2. Use Proxies and Rotate Them Accordingly
When you scrape a website, your IP address is visible to the site admin. They can easily detect if you’re collecting data. If you send too many requests from a single IP address, the site will automatically block your IP. Here’s where using a proxy server can be beneficial.
Proxies hide your original IP address and replace it with a random IP, making it difficult for the site to detect. Besides, even if the site detects and blocks the IP, your original IP will remain untouched.
To further enhance your scraping efficiency, create an assemblage of IPs, and use them randomly for each request. This way, you’ll send a smaller number of requests through multiple IPs instead of a heap of requests from a single IP. And since most anti-scraping programs work on request limit, you’ll be able to bypass them if you send a few requests from multiple proxies.
3. Look Out for Changing Layouts
Website owners have become smarter. Sometimes, they make it tricky for web scrapers by making subtle changes in the site layouts. For example, the website pages 1-15 might have the same layout, and the rest of the pages may display something different. Though the layout change might not be visible to a human eye, it blocks the scrapers from crawling.
To avoid this, be sure to scrape using CSS selectors or XPaths. If you can’t, look for layout alterations on the website and program your scraper accordingly to handle those pages.
4. Don’t Scrape Behind a Login
Some websites require you to seek permission to access web pages. If a web page has login protection, your scraper would need to send cookies or other information to view the page. The target website can easily detect and use these incoming cookies to access your credentials or block your access.
Therefore, it’s advisable to stay away from websites that have login protection. If you still want to scrape such websites, make sure you imitate human browsers to avoid getting detected.
5. Watch for Honeypot Traps
Website owners set up HTML links to detect hacking attempts and bot actions. These links, also known as honeypots, are invisible to human users but can be triggered by scrapers and crawlers. In most cases, these honeypots have “display: none” CSS style or a color similar to the page’s background.
However, implementing honeypot traps isn’t easy for website owners, as it requires intricate programming. Hence, honeypots are not very common nowadays.
6. Rotate User Agents
Every browser has a unique user agent, which gives the server information about the browser. In the absence of the user agent, you won’t be able to view a website’s content. Web scrapers usually don’t have user agents, so you’ll need to add them manually.
However, using the same user agent repeatedly can send a signal to the server that it’s a bot. So, it’s essential to keep changing your browsers’ user agent.
7. Use Headless Browsers
A solution to this hurdle is to use a headless browser like Puppeteer, Selenium, or Playright. Using Puppeteer or other headless browsers, you can exercise automated control of a web page by imitating a real web browser’s environment. As a result, your scraper won’t get detected, allowing you to scrape the site successfully.
8. Use VPNs
As a last resort, you can use VPNs (Virtual Private Networks) to bypass website blocks. It’ll make your IP address look like that of the target website’s and allow you to access its content. Since some websites block users from different regions, using VPNs will let them open blocked sites. However, it blocks companies from collecting anonymous data about their users, which is why VPNs are often blocked by websites.
Privacyenbescherming and Securicritic compare the best VPN services in a chart. You can find a comparison of various VPNs and their features there. It’s also useful for determining the best VPN to choose.
Anti-scraping tools are becoming more advanced and smarter with every passing day. But at its core, they’re all about detecting non-human behavior and a sudden increase in requests. So, if you can rotate your IP requests and imitate human behavior, you‘ll be able to scrape websites without getting blacklisted.