Here are several ways on how to prevent scraping of a website:
Use Robots.txt file
Add IP blocking
Use CAPTCHA
Limit the number of requests to website
Use a Content Delivery Network (CDN)
Monitor your website’s traffic
1. Use a Robots.txt File
Robots.txt is a file that tells search engines and web scrapers which pages on your website they can access. Make sure your robots.txt is clear and well-structured. Be clear on what areas you don’t want search engines or web scrapers to access.
It’s important to note that the robots.txt file serves as more of a suggestion, and while many search engines and web scrapers may honor the request within the file, there are also many others that ignore the file. This might not seem encouraging, but you should still have the robots.txt file set up.
2. Add IP Blocking
IP blocking is the process of restricting access to a website based on the IP address of the user. You can do this by adding code to your website's .htaccess file or through a firewall. The trick is to find out what the IP address of your web scraper is, as you can block them from accessing your entire website. As a note, in case the web scraper is using a proxy server, the IP blocking might not work, as they may switch IP addresses from time to time.
3. Use CAPTCHA
CAPTCHA is a type of verification test that is designed to be easy for humans to enter a site or application, but nearly impossible for automated tools like content scrapers. CAPTCHA is short for "Completely Automated Public Turing Test to Tell Computers and Humans Apart" and can be added to any form on your website, including any login pages. These act as a door, only allowing in anyone that passes a test.
If you plan to use CAPTCHA, it’s super important to make sure any tests aren’t impossible to solve, as you’re trying to allow people in, as some tests, like strange characters, may be difficult for users with dyslexia or other eye issues.
4. Limit the Number of Requests to the Website
When you limit the number of requests that can be made from an IP address or user agent to your website, you can help prevent web scraping. You can do this using rate limiting, which puts a cap on the number of requests that can be made over a period of time on your website. The result is that you can prevent web scrapers from inundating your website with a lot of requests, which could potentially cause it to crash.
5. Use a Content Delivery Network (CDN)
A Content Delivery Network, also known as a CDN, is a group of servers around the globe that work hand-in-hand to evenly and quickly deliver your website’s content to users wherever they are located. CDNs can help deter web scraping through caching your website and delivering static content, such as images and videos, from a local server instead of from the website's main server.
When a CDN does this, it can reduce the overall load on the main server and make it harder for web scrapers to scrape the website. Additionally, this is a layer of security, in case you want to prevent bots from brute force attempting to access your site, if you have a backend private area.
6. Monitor your Website’s Traffic
If you’re not monitoring your website’s traffic, you’re more than likely missing out on spotting any possible bots, which include any of them that are scraping the site. When you monitor your website’s traffic and identify common traffic sources that may seen suspicious, you can block them before they cause your website any serious problems.
Your website’s web host more than likely provides an area where you can access web server logs. In the case you don’t see anything to look into your website’s server logs, and you’re experiencing site issues, you can always ask your web host to look at the server logs and see if there are any possible bot issues happening. Aside from your server logs, you can also use your website analytics, like Google Analytics to determine if there’s any unusual web traffic behavior and from there, you can block any suspicious IP addresses.
