How to Avoid Blocking When Doing Web Scraping – Advanced Guide 2025

Web scraping is a powerful way to extract public data from the internet — but it can also be a delicate process. Many websites have advanced security systems specifically designed to detect and block automated requests. One of the biggest challenges in professional scraping is avoiding blocks, whether they’re IP-based or server-side.

In this article, we’ll dive into the best practices for avoiding blocks when doing web scraping, including proxy rotation, how to manage and bypass CAPTCHAs, and which tools and techniques you can use to scrape more securely, efficiently, and without triggering detection mechanisms.

Why Is My Scraping Being Blocked?

Before diving into solutions, it’s important to understand why scraping gets blocked. Websites employ multiple layers of defense against bots and automated scrapers. Some of the most common detection methods include:

• Suspicious traffic patterns: too many requests from the same IP.
• Repetitive browser signature or User-Agent.
• Excessive use of server resources.
• Non-human interaction (execution that’s too fast).
• CAPTCHAs and other verification systems.

So, how do you avoid these blocks? Let’s walk through each of the most effective methods step by step.

1. Proxy Rotation: A Key Technique to Avoid Blocks

What Is a Proxy?

A proxy acts as an intermediary between your machine and the target website. Instead of sending your requests directly from your local IP, you go through a proxy, which sends the request on your behalf. This allows you to hide your real identity, distribute requests, and reduce the likelihood of being blocked.

Why Proxy Rotation Works

Most websites can detect suspicious behavior if they receive too many requests from the same IP address. That’s where proxy rotation comes in.

By using a list of proxies and switching IPs after each request or group of requests, you drastically reduce the chance of being detected as a bot. This is especially useful when scraping at scale.

Types of Proxies and When to Use Each

Not all proxies are created equal. Here are the most commonly used types in the scraping ecosystem:

✅ Residential Proxies

• What are they? Assigned to real users via local ISPs.
• Pros: Very hard to detect, allow precise geolocation.
• Cons: More expensive, slower than other types.
• Best for: Scraping highly protected platforms like Amazon, LinkedIn, Yellow Pages, etc.

✅ Datacenter Proxies

• What are they? IP addresses provided by digital infrastructure providers.
• Pros: Fast, cheap, easy to integrate.
• Cons: Easily detected by major portals.
• Best for: Scraping less protected sites or controlled environments.

✅ Mobile Proxies

• What are they? IPs assigned to real mobile connections.
• Pros: Excellent for mobile scraping, high success rate.
• Cons: Less available, more costly.
• Best for: Scraping pages with advanced mobile protection.

✅ Shared Private Proxies

• What are they? IPs shared among several users.
• Pros: Cheaper than dedicated proxies.
• Cons: Might already be flagged if another user was reported.
• Best for: Small or test projects.

How to Implement a Proxy Rotation Strategy

There are several ways to implement proxy rotation depending on your scraping volume, target site type, and desired level of sophistication.

Basic Example in Python with requests and Proxy List

import requests
import random

proxies = [
    'http://user:pass@ip1:port',
    'http://user:pass@ip2:port',
    'http://user:pass@ip3:port'
]

url = 'https://target-site.com'

proxy = random.choice(proxies)

try:
    response = requests.get(url, proxies={"http": proxy, "https": proxy}, timeout=10)
    print("Response:", response.status_code)
except Exception as e:
    print("Error with current proxy:", e)

This script randomly selects a proxy from the list before making an HTTP request. It’s a basic starting point.

Using Automatic Rotating Proxy Services

Many platforms offer automatic rotating proxy services, eliminating the need to manually manage a list of IPs. Some examples include:

• Bright Data
• ScraperAPI
• ScrapingBee
• Smartproxy

These services automatically handle rotation, location selection, and even JavaScript rendering, saving time and preventing blocks.

2. Understanding CAPTCHAs and How They Affect Web Scraping

CAPTCHAs are visual or logic-based authentication tests designed to verify whether you’re using a human interface or a bot. They’re one of the main threats to any automated scraping project.

Common Types of CAPTCHA

How Do Websites Detect I’m Scraping?

CAPTCHAs aren’t just random. Many are triggered after detecting:

• Requests from known scraping IPs
• Unnatural headers
• Non-human navigation patterns
• Use of certain scraping libraries like Selenium (if not customized properly)

3. Strategies to Avoid or Bypass CAPTCHAs

While there’s no universal solution to beat CAPTCHAs, there are effective strategies that minimize their appearance or allow you to solve them when unavoidable.

📌 Strategy 1: Minimize CAPTCHA Activation

The best way to deal with CAPTCHAs is to avoid them altogether. You can do this by:

• Using residential proxies (less likely to trigger CAPTCHAs)
• Limiting request frequency (rate limiting)
• Using natural headers and rotating them
• Simulating human browsing with tools like Playwright or Puppeteer

📌 Strategy 2: Automatically Solve CAPTCHAs

When you can’t avoid them, there are services that solve CAPTCHAs automatically:

🔹 2captcha.com

• How it works: You send the CAPTCHA URL or token, and the service returns the answer.
• Integration: Simple APIs compatible with Python, Node.js, etc.
• Pros: Cheap, fast, supports many CAPTCHA types.
• Cons: Requires additional setup, may slow down scraping flow.

🔹 Anti-Captcha

• How it works: Similar to 2Captcha, with easy integration.
• Pros: Extended support, good technical support.
• Cons: Can be more expensive at high volumes.

4. Tools and Frameworks That Help Avoid Blocking

While traditional scraping might trigger alarms, some tools are specifically built to mimic human-like behavior.

🔧 PyDoll: A Modern Alternative That Reduces Detection

PyDoll is a Python-based web automation library inspired by Playwright. It allows you to navigate dynamic pages with full control over DOM events and HTTP requests. Its advantage over Selenium or Playwright is its low detection profile, making it an excellent alternative for avoiding blocks.

Advantages of PyDoll:

• High performance and low resource consumption
• Native integration with DevTools Protocol
• Granular control over navigation and requests
• Lower automation fingerprint compared to Selenium

Example Usage with Header Rotation:

from pydoll import launch
import random
import asyncio

HEADERS = [
    {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36",
        "Accept-Language": "es-ES,es;q=0.9,en;q=0.8"
    },
    {
        "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.0 Safari/605.1.15",
        "Accept-Language": "en-US,en;q=0.9"
    }
]

async def main():
    browser = await launch(headless=True)
    page = await browser.new_page()

    # Rotate headers before loading
    await page.set_extra_http_headers(random.choice(HEADERS))
    await page.goto('https://protected-page.com')

    content = await page.content()
    print(content[:500])

    await browser.close()

if __name__ == "__main__":
    asyncio.run(main())

Its ability to customize headers, simulate real browsing, and avoid automation signatures makes it ideal for complex scraping tasks.

🔧 Other Professional Tools That Reduce Blocking

⚙️ Playwright

• What it offers: Controlled browser with high customization.
• Pros: JS rendering, easy to use, low detection footprint.
• Cons: May require proxies for large-scale use.

⚙️ Puppeteer (Node.js)

• What it offers: Similar to Playwright, but in a Node.js environment.
• Pros: Large community, many plugins.
• Cons: Needs extra patches to avoid detection.

⚙️ Selenium + Undetected Chromedriver

• What it offers: Controlled browser navigation with modified ChromeDriver to avoid detection.
• Pros: Full browser control.
• Cons: Requires constant tweaking, resource-heavy.

⚙️ Apify Cheerio Scraper

• What it offers: High-performance scraping engine without JS rendering.
• Pros: Very fast, ideal for large volumes of static HTML.
• Cons: Not suitable for dynamic pages.

5. Technical Best Practices to Avoid Blocking

In addition to using smart proxies and tools, here are best practices every scraper developer should follow:

🛡️ Rotate User-Agents and Headers

Using the same User-Agent or set of headers is a red flag for servers. Use this practice:

import requests
import random

user_agents = [
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36",
    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36",
    "Mozilla/5.0 (iPhone; CPU iPhone OS 16_0_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148"
]

headers = {
    "User-Agent": random.choice(user_agents),
    "Accept-Language": "en-US,en;q=0.9",
    "Accept-Encoding": "gzip, deflate, br",
    "Connection": "keep-alive"
}

response = requests.get("https://site.com", headers=headers)
print(response.text[:200])

⏳ Random Intervals Between Requests

Avoid regular intervals. Use random delays:

import time
import random

time.sleep(random.uniform(1, 3))  # Wait between 1 and 3 seconds

🧠 Use Sessions and Cookie Management

Simulate real browsing by using persistent sessions and cookies:

from requests_html import HTMLSession

session = HTMLSession()
response = session.get("https://page.com")
response.html.render()  # JavaScript rendering

6. Conclusion: Avoid Blocking with Professional Techniques

Automated scraping remains a fundamental tool for businesses, researchers, and entrepreneurs — but it’s also a sensitive activity requiring technical care to avoid detection.

To avoid blocks while scraping:

• Use rotating proxies, especially residential or mobile ones.
• Rotate User-Agents and headers.
• Avoid aggressive scraping with random delays.
• Use professional tools like PyDoll, Playwright, or ScrapingBee.
• Handle CAPTCHAs with auto-solving services like 2Captcha or Anti-Captcha.
• Monitor your logs to catch early signs of blocking.

With these strategies, you’ll be able to extract data securely, ethically, and reliably — even on platforms with advanced protection.