This guide is for mid-to-large companies. These companies often use web scraping for data extraction. Getting blocked can disrupt this process. We’ll show you how to avoid it.
Why Do Websites Block Web Scrapers?
Websites block scrapers for several reasons:
- Server Load: Too many requests can overload a website’s servers.
- Data Protection: They want to protect their data from competitors.
- Terms of Service: Scraping might violate their terms of service.
7 Techniques to Avoid Getting Blocked
Here are seven proven techniques. They will help you scrape data successfully in 2025.
1. IP Rotation: The Foundation of Stealth Scraping
If you make too many requests from one IP address, websites will block you. IP rotation solves this.
- How it Works: You use multiple IP addresses. This makes it look like requests are coming from different users.
- Methods:
- Proxy Servers: A proxy acts as an intermediary. It forwards your requests using its own IP address. This is the most common and often most effective method.
- Benefits:
- Hides your real IP address.
- Allows many requests.
- Easy to switch IPs.
- Benefits:
- VPNs (Virtual Private Networks): A VPN encrypts your traffic and routes it through a server in a different location. VPNs are good for general privacy. They are often less effective for large-scale scraping than dedicated proxy services.
- Rotating IP Services: These services provide a pool of IP addresses. They automatically switch between them. This is the easiest method.
- Proxy Servers: A proxy acts as an intermediary. It forwards your requests using its own IP address. This is the most common and often most effective method.
- Example (Conceptual – using a hypothetical proxy service):
“`python
import requests
# Your target website
target_url = ‘https://www.example.com’
# Request through a proxy service (replace with actual service)
proxied_url = ‘https://proxyservice.com?url=’ + target_url
response = requests.get(proxied_url)
print(response.text)
“`
- Recommended Providers: Check out this list of popular proxy providers (replace with a real, relevant, and active link to a reputable comparison or list, or remove if unavailable).
2. Set a Realistic User-Agent Header
A User-Agent tells the website what browser you’re using. Websites may block requests from unknown User-Agents.
- What to Do: Set a User-Agent that looks like a common web browser (Chrome, Firefox, etc.).
- Example (Python):
- Python
import requests
headers = {
‘User-Agent’: ‘Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36’
}
response = requests.get(‘https://www.example.com’, headers=headers)
print(response.text)
- Important: Keep your User-Agent up-to-date. Browser versions change. Find a list of popular User Agents (replace with a real, active, and relevant link, or remove if unavailable).
3. Set Other HTTP Request Headers (Mimic a Real Browser)
To look even more like a real user, set other headers.
- Key Headers:
- Accept: Specifies the types of content the browser accepts.
- Accept-Encoding: Indicates supported compression methods (e.g., gzip).
- Accept-Language: Specifies the user’s preferred language.
- Upgrade-Insecure-Requests: Tells the server the browser prefers secure connections.
- Example (Python):
- Python
import requests
headers = {
‘User-Agent’: ‘Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36’,
‘Accept’: ‘text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8’,
‘Accept-Encoding’: ‘gzip, deflate, br’,
‘Accept-Language’: ‘en-US,en;q=0.9’,
‘Upgrade-Insecure-Requests’: ‘1’
}
response = requests.get(‘https://www.example.com’, headers=headers)
print(response.text)
- Referer Header (Optional): Some websites check where you came from. You can set the Referer header to make it look like you clicked a link from another page. Use this carefully, as it can be misleading.
- Python
headers[‘Referer’] = ‘https://www.google.com’ # Example
- Resource: For a more in-depth guide, read about how to use Headers for web scraping (replace with a real, active, and relevant link, or remove if unavailable).
4. Randomize Delays Between Requests (Be Polite)
Don’t bombard the website with requests. Space them out.
- Why? Rapid requests look like a bot. They can also overload the server.
- How? Use time.sleep() in Python. Add random delays.
- Example (Python):
- Python
import requests
import time
import random
for i in range(10):
response = requests.get(‘https://www.example.com/page/’ + str(i))
print(response.status_code)
time.sleep(random.uniform(2, 6)) # Wait 2-6 seconds
- robots.txt: Check the website’s robots.txt file (e.g., https://www.example.com/robots.txt). It might specify a crawl delay. Respect it!
5. Set a Referrer (Use with Caution)
The Referer header tells the website where the request appears to be coming from.
- Use Sparingly: Misusing the Referer header can be seen as deceptive. Only use it if it genuinely makes sense in the context of your scraping.
- Example
Python
import requests
url = “https://www.example.com/target-page”
headers = {
“Referer”: “https://www.google.com/”
}
response = requests.get(url, headers=headers)
6. Use a Headless Browser (For Complex Websites)
Some websites use JavaScript to load content. Simple requests might not get everything. A headless browser solves this.
- What is it? A web browser without a visible window. It runs in the background.
- Why use it?
- It renders JavaScript.
- It can simulate user interactions (clicks, scrolls).
- It’s less likely to be detected (compared to very basic scrapers).
- Popular Choices:
- Selenium: A powerful and versatile automation tool.
- Playwright: A newer tool, often faster and easier to use than Selenium.
- Puppeteer: Developed by Google, primarily for Chrome/Chromium.
- Example (Selenium – very basic):
- Python
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
from selenium.webdriver.chrome.service import Service
# Use headless mode
options = Options()
options.add_argument(“–headless”)
#service = Service(‘/path/to/chromedriver’) # Path
driver = webdriver.Chrome(options=options)
driver.get(‘https://www.example.com’) # Replace
print(driver.title) # Get the page title
driver.quit()
- Guide: If the website uses a JavaScript framework, see this guide on how to scrape data from a website built with a JavaScript framework (replace with a real, active, and relevant link, or remove).
7. Avoid Hidden Traps (Honeypots)
Some websites set traps for bots. These are often invisible links. Real users won’t click them.
- How to Spot Them:
- display: none; in the HTML style.
- visibility: hidden; in the HTML style.
- Links that are the same color as the background.
- What to Do: Inspect the HTML carefully. Don’t follow links with these attributes.
FAQ
- What is the best way to avoid getting blocked?
- A combination of IP rotation, realistic headers, and delays is most effective.
- Is web scraping legal?
- It depends. Always check the website’s terms of service and robots.txt. Don’t scrape personal data without permission.
- What is a headless browser?
- A web browser that runs without a visible window. It’s used for automation.
- What is a proxy server?
- A server that acts as an intermediary between you and the website. It hides your IP address.
- What is a User-Agent?
- A string that identifies your browser to the website.
- How often should I rotate my IP address?
- It depends on the target website. Some sites are more sensitive than others. Start with a conservative approach (e.g., rotate every few requests) and adjust as needed.
- What happens if my IP address gets blocked? * You won’t be able to access the website from that IP address. This is why IP rotation is so crucial.
Conclusion
Web scraping can be challenging. Websites actively try to prevent it. By using these techniques, you can significantly reduce your chances of getting blocked. Remember to scrape responsibly and ethically.
Need help with web scraping or data extraction? Avoid the headaches of getting blocked. We’ll handle the complexities, so you can focus on using your data.
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