How to Avoid Getting Blocked While Scraping

Getting blocked is the most common frustration in web scraping. Websites use sophisticated anti-bot systems to detect and block scrapers. Here are proven techniques to avoid detection.

Why You Get Blocked

Websites detect scrapers through:

• IP reputation, known datacenter or previously flagged IPs
• Request patterns, too fast, too regular, or unnatural navigation
• Browser fingerprinting, missing or inconsistent browser signals (canvas, WebGL, TLS/JA3, User-Agent)
• Header analysis, missing or suspicious HTTP headers
• CAPTCHAs, challenge-response tests for suspected bots

You can run our free Browser Fingerprint Check against your own scraper first to see which of these signals leaks, before you go rewriting code.

Technique 1: Rotate Proxies

Never scrape from a single IP address:

import requests
import random

proxies = [
    "http://user:pass@proxy1:8080",
    "http://user:pass@proxy2:8080",
    "http://user:pass@proxy3:8080",
]

def scrape_with_rotation(url):
    proxy = random.choice(proxies)
    return requests.get(url, proxies={"http": proxy, "https": proxy})

Or let ScraperAPI handle rotation automatically:

import requests

response = requests.get("https://api.scraperapi.com", params={
    "api_key": "YOUR_KEY",
    "url": "https://example.com/target"
})
# Proxies are rotated automatically

Technique 2: Use Realistic Headers

import requests
import random

user_agents = [
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 Chrome/125.0.0.0 Safari/537.36",
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 Chrome/125.0.0.0 Safari/537.36",
    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 Chrome/125.0.0.0 Safari/537.36",
]

headers = {
    "User-Agent": random.choice(user_agents),
    "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
    "Accept-Language": "en-US,en;q=0.9",
    "Accept-Encoding": "gzip, deflate, br",
    "Connection": "keep-alive",
    "Upgrade-Insecure-Requests": "1",
}

response = requests.get("https://example.com", headers=headers)

Technique 3: Add Random Delays

import time
import random

def human_delay():
    """Simulate human-like browsing delays"""
    delay = random.uniform(2, 5) + random.gauss(0, 0.5)
    time.sleep(max(1, delay))

for url in urls:
    response = requests.get(url, headers=headers)
    human_delay()

Technique 4: Handle CAPTCHAs

ScraperAPI and ScrapingAnt handle CAPTCHAs automatically:

# ScraperAPI solves CAPTCHAs automatically
response = requests.get("https://api.scraperapi.com", params={
    "api_key": "YOUR_KEY",
    "url": "https://protected-site.com/page",
    "render": "true"
})
# CAPTCHA solved, content returned

Technique 5: Manage Sessions and Cookies

session = requests.Session()

# Visit the homepage first (like a real user)
session.get("https://example.com", headers=headers)
time.sleep(2)

# Then navigate to your target
response = session.get("https://example.com/products", headers=headers)

Technique 6: Render JavaScript

Many anti-bot systems check for JavaScript execution:

# ScrapingAnt renders JavaScript on every request
response = requests.get("https://api.scrapingant.com/v2/general", params={
    "x-api-key": "YOUR_KEY",
    "url": "https://protected-site.com",
    "browser": "true"
})

The Simplest Approach

Instead of implementing all these techniques yourself, use a scraping API that handles everything:

Technique	DIY	ScraperAPI/ScrapingAnt
Proxy rotation	Manual setup	Automatic
Header management	Manual	Automatic
CAPTCHA solving	Third-party service	Built-in
JS rendering	Playwright/Selenium	One parameter
Rate limiting	Manual	Built-in

Verdict

The most reliable way to avoid getting blocked is to use a managed scraping API like ScraperAPI or ScrapingAnt. They implement all anti-detection techniques automatically, achieving 95-99% success rates even on heavily protected sites. For DIY scraping, combine proxy rotation, realistic headers, random delays, and JavaScript rendering for the best results.