Kasada is a popular web application firewall service used by many websites like Realestate, Hyatt and Scheels. It detects and blocks bots from accessing web, mobile, and API applications.
In this article, we'll explain what Kasada is and how it's used to block bots such as web scrapers. Then, we'll go over techniques and tools to use in order to avoid Kasada scraping blocking. Let's get started!
Key Takeaways
Master Kasada bypass techniques using multi-layered detection analysis, fingerprinting countermeasures, and advanced anti-bot protection strategies for successful web scraping.
- Implement Kasada bypass strategies using sophisticated WAF detection analysis including TLS fingerprinting, HTTP analysis, IP reputation, and JavaScript challenges
- Configure trust score system analysis by understanding how Kasada calculates weighted scores based on various fingerprinting techniques
- Apply TLS fingerprinting countermeasures by using JA3-resistant libraries and avoiding detectable cipher suites and TLS versions
- Implement HTTP fingerprinting evasion by using realistic headers, user agents, connection patterns, and human-like timing
- Use IP reputation management by avoiding known datacenter IPs, VPN ranges, and suspicious geographic patterns that trigger scrutiny
- Configure JavaScript challenge bypass using headless browsers with human-like behavior and behavioral analysis countermeasures
- Apply comprehensive bypass approach using residential proxies, realistic fingerprints, proper headers, and headless browsers with human-like behavior
- Use professional tools like Scrapfly for pre-configured solutions that handle Kasada's complex detection mechanisms
What is Kasada?
Kasada is a WAF service used to protect websites from malicious activities, such as fraud, spam, and brute forcing. It can detect requests coming from bots by studying and analyzing the configuration differences between bots and normal users' behavior.
Kasada can affect us as web scrapers if the traffic is detected as coming from bots. So, let's have a look at common Kasada detection errors and how they work in action.
How to Identify Kasada Detection?
Unlike other WAF services, Kasada doesn't suspect a group of requests and then identify them by challenging them with CAPTCHAs. Instead, they suspect all requests, even normal users, and challenge them with hidden protection layers located on both the server and client sides. These challenges exhaust bots and bad actors while passing normal users. Leading the firewall to learn from the failed requests' traces to enhance the protection algorithm.
The most common detection errors encountered while getting blocked by Kasada are 400-500 status codes. The 400 errors represent client-side issues, while the 500 represent server-side ones. This reflects the Kasada protection layers implemented on both the client and server sides. The Kasada blocking errors are usually associated with some custom headers used by Kasada, such as the X-Kpsdk-Ct header.
How Does Kasada Detect Web Scrapers?
Before Kasada decides whether the request sender is a bot or not, it uses different techniques to analyze the request fingerprint to calculate a score called the trust score.
The trust score is calculated after going through a few stages. Each stage has a score, and the final score is a weighted average of the previous stages. Kasada decides whether to block or allow the request depending on this final score.
This process seems complicated and overwhelming for developers to manage. However, if we look at the details of these stages and implement the best practices in each one, we'll have a high chance of bypassing Kasada bot protection. So, let's go through each stage!
TLS Fingerprinting
The TLS is a protocol used to establish a secure and encrypted HTTPS channel between a client and a web server. Before this channel is initialized, both the client and server have to go through a process called the TLS handshake. During this process, both parties have to negotiate certain values in order to establish the connection. These are:
- Cipher Suites
List of encryption algorithms supported by both client and server, ordered by priority. The server and client agree on the first matching value. - TLS Versions
The TLS version used by the client browser, typically it's either 1.2 or 1.3. - Enabled Extensions
List of features the client supports alongside some metadata, such as the server domain name.
The above TLS details are combined together to create a JA3 fingerprint. A string token separated by a - character:
772,4865-4866-4867-49195-49199-49196-49200-52393-52392-49171-49172-156-157-47-53,16-18-13-5-23-45-10-35-65281-27-51-0-11-65037-43-17513,29-23-24,0
To make your request fingerprint appear normal and avoid blocking, ensure that the libraries and tools used while establishing the HTTP connection are JA3-resistant. To do that, you can use the ScrapFly JA3 fingerprint web tool, which identifies and shows your fingerprint.
IP Address Fingerprinting
The next stage of calculating the trust score is the IP address fingerprinting. Firewalls like Kasada can identify the IP address of the request sender. In which they get information about the client's location, ISP and other related details.
The most viable metric here is the IP address type, which falls into three categories:
- Residential
IP addresses are assigned to home networks by ISPs. Residential IPs have a positive trust score as they are most likely used by real users. However, these IPs are few and expensive to acquire. - Mobile
IP addresses are assigned to phones using mobile network towers. Mobile IPs have a positive trust score as they are used by real users too. These IPs are also dynamic that change over a specific period of time, making it hard for firewalls to identify and track them. - Datacenter
IP addresses are assigned by cloud data centers, such as AWS and Google Cloud. Datacenter IPs have a negative trust score as they are likely used by scripts and bots.
To avoid Kasada scraping blocking, you need to hide your IP address by splitting the requests over multiple IP addresses. This will make it harder for the firewall to detect and block your IP address.
HTTP Details
The next step of the trust calculation process is analyzing the request HTTP details themselves. As the HTTP protocol gets more complex, it has become easier for firewalls to detect connections from bots and web scrapers. Kasada can identify the request as coming from bots by comparing the HTTP version and headers with those used by normal browsers.
- HTTP version
Most of the web currently runs over HTTP2 or even HTTP3, while many HTTP clients still use HTTP1.1. So, if the HTTP version of the request is HTTP1.1, Kasada will likely detect and block this request.
Some clients support HTTP2, like httpx and cURL, though it's not enabled by default. HTTP2 is also exposed to HTTP2 fingerprinting, which can be used to identify web scrapers. Try out the ScrapFly HTTP2 fingerprint test page for more details.
- HTTP headers
HTTP headers are key-value pairs used to transfer essential information about the request between the client and server. Many firewalls like Kasada usually look for missing or miss-configured headers like the User-Agent, Referrer and Origin
To avoid getting blocked by Kasada, ensure your requests use HTTP2 and match your headers with those of normal users.
JavaScript Fingerprinting
The final stage of calculating the trust score is the JavaScript fingerprinting, though it's the most complex step. Kasada analyzes the client's JavaScript for details like:
- Hardware details and capabilities
- JavaScript runtime details
- Web browser infomation
- Operating system information
The above data are combined together to create a unique fingerprint. This data seems overwhelming to manage. But luckily for us, the JavaScript fingerprint isn't a reliable method and its results aren't taken with a grain of salt by firewalls. So, regardless of this stage score, requests can avoid Kasada blocking if the trust score of the previous stages is high.
To bypass Kasada JavaScript fingerprinting, we can follow two different methods.
Reverse engineer the JavaScript fingerprint
By following this step, we can counter the Kasada fingerprint by feeding the client with fake data. However, this method is complex and time-consuming. Moreover, it requires continuous maintenance and updates, as the methods used are constantly changing.
Use headless browsers
This approach is much easier and straightforward - simply run headless browsers such as Selenium, Playwright and Puppeteer. However, this method is considered slow, as headless browsers require a lot of resources.
To avoid Kasada scraping blocking from JavaScript fingerprinting, use headless browsers to navigate and scrape the web pages. However, not all headless browser tools are equally effective - see the stealth tool recommendations below for 2026-specific tools that work best against Kasada.
Behavior Analysis
While following the previous steps and implementing the best practices of each one, Kasada can still detect and block web scraping requests. This is because the detection algorithm learns from the requests and analyzes patterns constantly.
This means that the trust score can be decreased over time. For that, changing the web scraping traffic is necessary to ensure the highest success rate against Kasada bot detection. For example, you need to rotate proxies, User-Agents and header values. The same idea can be applied to headless browsers by changing the browsing profile and capabilities, such as the browser name, version, and screen size.
How to Bypass Kasada Bot Management?
Now that we've covered all of the detection methods that Kasada uses to identify bots, let's put it all together with specific tools and strategies to bypass Kasada:
- Use high-quality residential or mobile proxies to maintain a positive IP trust score
- Use modern stealth browser automation tools instead of vanilla Selenium or Puppeteer
- Warm up scraper sessions before targeting data pages
- Rotate fingerprints across multiple profiles to avoid behavior detection
- Distribute traffic through multiple agents with varied configurations
Let's take a look at the best tools and practices for each of these strategies.
Try Nodriver
Nodriver is the successor to undetected-chromedriver and is one of the most effective tools for bypassing Kasada. Instead of patching ChromeDriver like its predecessor, Nodriver communicates directly with Chrome via the DevTools Protocol, making it fundamentally harder for Kasada to detect.Why Nodriver?
Unlike traditional Selenium-based solutions, Nodriver uses a completely different approach to browser automation:
- No WebDriver patches needed - Since it doesn't use ChromeDriver at all, there's no
navigator.webdriverflag to detect - Direct Chrome DevTools Protocol - Communicates with Chrome natively, avoiding common automation signatures
- Native stealth capabilities - Built-in anti-detection features without additional plugins
- Active development - Regularly updated to counter new detection methods used by Kasada
- Better performance - Lower overhead compared to traditional Selenium setups
Nodriver Example for Kasada Bypass
import nodriver as uc
import asyncio
async def main():
browser = await uc.start()
page = await browser.get('https://scrapfly.io/web-scraping-tools/browser-fingerprint')
# Wait for the page to fully load
await page.sleep(5)
# Take a screenshot to show the browser fingerprint results
await page.save_screenshot('nodriver_fingerprint.png')
print("Screenshot saved as nodriver_fingerprint.png")
# Get the page content
content = await page.get_content()
print(content)
browser.stop()
uc.loop().run_until_complete(main())
Nodriver's async architecture and native stealth make it a strong choice for bypassing Kasada's JavaScript fingerprinting and behavior analysis.
Try SeleniumBase UC Mode
SeleniumBase with its UC (Undetected Chrome) mode provides a production-ready solution for bypassing Kasada. It wraps undetected-chromedriver features into a well-maintained, feature-rich framework that offers automatic updates and built-in stealth capabilities.SeleniumBase Advantages
- Production-ready framework - Includes test runners, assertions, and reporting tools
- Automatic ChromeDriver management - Handles driver updates and version matching
- Built-in UC mode - Enables fingerprint resistance with a single flag
- Active maintenance - Regular updates to counter new Kasada detection techniques
- Rich API - Provides helper methods for common scraping tasks like waiting, clicking and scrolling
SeleniumBase Example
from seleniumbase import SB
with SB(uc=True) as sb:
sb.open("https://scrapfly.io/web-scraping-tools/browser-fingerprint")
# UC mode handles Kasada's fingerprint checks automatically
sb.sleep(5)
# Take a screenshot to show the browser fingerprint results
sb.save_screenshot("seleniumbase_fingerprint.png")
print("Screenshot saved as seleniumbase_fingerprint.png")
# Access page content
page_source = sb.get_page_source()
print(page_source)
SeleniumBase UC mode is ideal if you're already familiar with Selenium-style APIs and need a drop-in upgrade with stealth capabilities.
Try Camoufox (Firefox-Based Alternative)
Camoufox takes a different approach. A modified Firefox build designed from the ground up to be undetectable. Since most anti-bot tools like Kasada focus heavily on Chrome-based detection, using a Firefox-based solution can provide a significant advantage.Camoufox Benefits
- Firefox-based - Avoids Chrome-specific detection since most anti-bots focus on Chromium
- Hardened fingerprint resistance - Modified browser internals to prevent fingerprinting leaks
- Playwright-compatible - Uses the familiar Playwright API for ease of use
- Different TLS fingerprint - Firefox's TLS stack generates different JA3 fingerprints than Chrome
- Less targeted by anti-bots - Firefox automation is less commonly blocked than Chrome automation
Camoufox Example
from camoufox.sync_api import Camoufox
with Camoufox() as browser:
page = browser.new_page()
page.goto('https://scrapfly.io/web-scraping-tools/browser-fingerprint')
# Wait for the page to fully load
page.wait_for_timeout(5000)
# Take a screenshot to show the browser fingerprint results
page.screenshot(path='camoufox_fingerprint.png')
print("Screenshot saved as camoufox_fingerprint.png")
# Get page content
content = page.content()
print(content)
Camoufox is a great alternative when Chrome-based tools are consistently being detected by Kasada.
Try curl-impersonate
curl-impersonate is a community tool that fortifies thelibcurl HTTP client library to mimic the behavior of a real web browser. It patches the TLS, HTTP2 and JavaScript fingerprints to make HTTP requests appear as if they're coming from a real browser.This is useful for bypassing Kasada's TLS and HTTP fingerprinting stages without the overhead of running a full browser. However, it won't bypass Kasada's JavaScript challenges, so it works best for endpoints that rely primarily on connection-level fingerprinting.
However, this works only for curl-powered web scrapers which can be difficult to use compared to modern HTTP clients like httpx or requests. For more, see how to scrape with curl intro.
Try Warming Up Scrapers
Kasada's behavior analysis tracks the full browsing session, not just individual requests. Jumping directly to a target data page without any prior browsing history looks suspicious and often triggers blocks.
Session warming means simulating a natural browsing pattern before scraping target pages:
- Start by visiting the website's homepage
- Navigate to a few intermediary pages (category pages, search pages)
- Add random delays between each navigation (2-5 seconds)
- Only then navigate to the target scraping pages
import nodriver as uc
import random
async def main():
target_url = 'https://web-scraping.dev/product/1'
browser = await uc.start()
# Step 1: Visit homepage first
page = await browser.get('https://web-scraping.dev/')
await page.sleep(random.uniform(2, 4))
# Step 2: Visit a category or intermediary page
await page.get('https://web-scraping.dev/products')
await page.sleep(random.uniform(1, 3))
# Step 3: Now navigate to the target page
await page.get(target_url)
await page.sleep(2)
content = await page.get_content()
browser.stop()
return content
uc.loop().run_until_complete(main())
This warming approach establishes a legitimate-looking trust score before accessing the pages you actually want to scrape.
Rotate Real User Fingerprints
Sending all requests with the same fingerprint profile makes it easy for Kasada to detect and block scraping patterns over time. To avoid this, rotate fingerprint profiles across your scraping sessions:
- Browser versions - Alternate between different Chrome and Firefox versions
- Operating systems - Vary between Windows, macOS, and Linux user agents
- Screen resolutions - Randomize viewport sizes (e.g., 1920x1080, 1366x768, 1440x900)
- Language and locale - Switch between
en-US,en-GB, and other common locales - Timezone - Match the timezone to the proxy's geographic location
Combine fingerprint rotation with proxy rotation for maximum effectiveness:
import random
PROFILES = [
{
"user_agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36",
"viewport": {"width": 1920, "height": 1080},
"locale": "en-US",
},
{
"user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36",
"viewport": {"width": 1440, "height": 900},
"locale": "en-GB",
},
{
"user_agent": "Mozilla/5.0 (X11; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0",
"viewport": {"width": 1366, "height": 768},
"locale": "en-US",
},
]
def get_random_profile():
return random.choice(PROFILES)
# Example: apply a profile when launching a Playwright browser context
profile = get_random_profile()
context = await browser.new_context(
user_agent=profile["user_agent"],
viewport=profile["viewport"],
locale=profile["locale"],
)
Pass these profile values when launching your browser — for example, set viewport, user_agent, and locale when creating a Playwright browser_context. Each scraping session or batch of requests should use a different profile paired with a different proxy IP to make the traffic appear as if it's coming from many distinct users.
Bypass Kasada With ScrapFly
Bypassing Kasada anti-bot while possible is very difficult - let Scrapfly do it for you!
ScrapFly provides web scraping, screenshot, and extraction APIs for data collection at scale. Each product is equipped with an automatic bypass for any anti-bot system and we achieve this by:
- Maintaining a fleet of real, reinforced web browsers with real fingerprint profiles.
- Millions of self-healing proxies of the highest possible trust score.
- Constantly evolving and adapting to new anti-bot systems.
- We've been doing this publicly since 2020 with the best bypass on the market!
It takes Scrapfly several full-time engineers to maintain this system, so you don't have to!
For example, to scrape pages protected by Kasada using ScrapFly's Python SDK all we need to do is enable the Anti Scraping Protection bypass feature:
from scrapfly import ScrapflyClient, ScrapeConfig, ScrapeApiResponse
scrapfly = ScrapflyClient(key="Your ScrapFly API key")
result: ScrapeApiResponse = scrapfly.scrape(ScrapeConfig(
url="https://scrapfly.io/web-scraping-tools/browser-fingerprint",
# select a the proxy country
country="us",
# enable the ASP to bypass any website's blocking
asp=True,
# enable JS rendering, similar to headless browsers
render_js=True,
))
# get the page HTML content
print(result.scrape_result['content'])
Troubleshooting Kasada Blocks
Even with the best techniques, you may still encounter Kasada blocks. Here's how to diagnose and fix common issues:
1. Getting 403 or 429 Errors on First Request
Problem: Immediate blocks before any scraping begins
Solutions:
- Verify TLS fingerprint - Use ScrapFly's JA3 fingerprint tool to check if your fingerprint matches a real browser
- Enable HTTP2 - Most Kasada-protected sites expect HTTP2; ensure it's enabled in your HTTP client
- Check User-Agent - Must match a current browser version (Chrome 131+, Firefox 132+ as of 2026)
- Switch IP type - If using datacenter IPs, switch to residential or mobile proxies
2. Blocks After Several Successful Requests
Problem: First few requests work, then blocks start appearing
Solutions:
- Implement rate limiting - Add random delays of 2-5 seconds between requests
- Rotate IP addresses - Use proxy rotation to distribute requests across multiple IPs
- Vary request patterns - Don't request pages in predictable sequential order
- Rotate browser fingerprints - Change screen resolution, OS, and browser version between sessions
3. Browser Automation Detected Immediately
Problem: Blocks even when using Selenium/Puppeteer/Playwright
Solutions:
- Switch to modern tools - Use Nodriver, SeleniumBase UC, or Camoufox instead of vanilla Selenium
- Disable automation flags - Remove
navigator.webdriverand other automation indicators - Use real browser profiles - Launch browsers with actual user data directories
- Add human-like delays - Random delays between actions (mouse movements, clicks, scrolling)
4. Residential Proxies Still Getting Blocked
Problem: Using residential proxies but still encountering blocks
Solutions:
- Check proxy quality - Some residential proxy providers sell flagged or overused IPs
- Match proxy location to headers - Ensure your
Accept-Language, timezone and locale match the proxy's country - Reduce per-IP request volume - Even residential IPs can be flagged if they send too many requests
- Try mobile proxies - Mobile IPs are generally harder for Kasada to flag due to shared usage patterns
5. Kasada X-Kpsdk-Ct Header Errors
Problem: Responses contain Kasada-specific headers like X-Kpsdk-Ct indicating challenge failure
Solutions:
- Ensure JavaScript execution - Kasada requires JavaScript challenges to be completed; plain HTTP clients can't handle this
- Use a stealth browser - Switch to Nodriver, Camoufox or SeleniumBase UC which can process these challenges
- Warm up the session - Visit the homepage first to establish trust before hitting API endpoints
- Check for CAPTCHA loops - If stuck in a challenge loop, try a fresh browser profile and new proxy IP
FAQ
To wrap up this guide, let's take a look at some frequently asked questions about bypassing Kasada bot detection.
Is it legal to scrape Kasada-protected pages?
Yes, as long as the data is public, then it's legal to scrape them. However, you should keep your scraping rate reasonable to avoid damaging the website.
Is it possible to bypass Kasada using Cache services?
Yes, you can use the cached pages provided by public cache services such as Google Cache and Archive.org to bypass Kasada. However, these pages might not always be up-to-date, resulting in scraping obsolete data.
Is it possible to bypass Kasada entirely and scrape the website directly?
This would fall into security flaws and vulnerabilities, which isn't advised to do while scraping as it may lead to legal concerns.
What are other anti-bot service?
There are many WAF services used to protect websites from bots and cyber-attacks, such as Cloudlfare, Akami, Datadome, PerimeterX and Imperva Incapsula. These anti-bots function almost in the same way and the technical aspects described in this article can applied to them too.
Can I Use Python requests library to bypass Kasada?
No, the Python requests library alone cannot bypass Kasada. It doesn't support HTTP2, generates a detectable TLS fingerprint, and cannot execute JavaScript challenges. You need either a stealth browser tool like Nodriver or SeleniumBase UC, or a specialized API like ScrapFly that handles these detection layers for you.
Which stealth browser tool is best for Kasada bypass?
Nodriver and Camoufox are the most effective options. Nodriver works well for Chrome-based bypasses, while Camoufox provides a Firefox-based alternative that avoids Chrome-specific detection. SeleniumBase UC mode is a solid choice for production environments that need a mature testing framework.
How fast can I scrape Kasada-protected sites?
Kasada monitors request frequency closely. For sustained scraping, limit yourself to 1-3 requests per second per IP address with random delays in between. Using multiple rotating proxies allows you to increase total throughput while keeping per-IP rates low. Faster rates will quickly trigger Kasada's behavior analysis and lead to blocks.
Does Kasada use CAPTCHAs?
Unlike many other anti-bot services, Kasada does not primarily rely on visible CAPTCHAs. Instead, it uses hidden JavaScript challenges, called "proof of work" puzzles, that the client must solve transparently. If the client fails these challenges, the request is blocked outright rather than presented with a CAPTCHA.
Summary
Kasada is an anti-bot. A WAF service that's used to detect and block web scrapers by trapping them with hidden challenges. Kasada detects web scrapers using various techniques, such as HTTP details, TLS, IP, and JavaScript fingerprinting.
We have explained how to bypass Kasada while scraping using different steps. In a nutshell, these are:
- Use a resistant JA3 fingerprint.
- Use proxies to hide your IP address.
- Use headers similar to normal users and enable HTTP2.
- Use modern stealth browser tools like Nodriver, SeleniumBase UC, or Camoufox.
- Warm up scraper sessions before targeting data pages.
- Rotate fingerprints across multiple browser profiles.
Legal Disclaimer and Precautions
This tutorial covers popular web scraping techniques for education. Interacting with public servers requires diligence and respect and here's a good summary of what not to do:- Do not scrape at rates that could damage the website.
- Do not scrape data that's not available publicly.
- Do not store PII of EU citizens who are protected by GDPR.
- Do not repurpose the entire public datasets which can be illegal in some countries.