For those who work with web crawlers or automation, the biggest headache is anti-crawling detection. Tools like Cloudflare Turnstile, reCAPTCHA, and FingerprintJS can easily block attempts using regular browsers or libraries like Selenium/Puppeteer. CloakBrowser is designed to solve this problem.
What is CloakBrowser?
In a nutshell, it’s an invisible browser that modifies the browser’s “fingerprint” at the Chromium C++ source code level. It doesn’t rely on JavaScript injections or configuration patches; instead, it directly modifies the Chromium code itself. As a result, anti-crawling systems see it as a normal browser, because that’s what it is.
CloakBrowser is open-source, licensed under the MIT License, and has received over 24,000 stars on GitHub.
Core Features:
1. 58 C++ source code patches
These patches cover almost all aspects of fingerprint detection:
- Canvas fingerprints
- WebGL fingerprints
- Audio fingerprints
- Font lists
- GPU information
- Screen parameters
- WebRTC leaks
- Network timing
- Automation signals (CDP detection)
- Input behavior simulation
These modifications are made at the browser compilation stage, not at runtime with JavaScript injections, so the websites being tested don’t detect anything unusual.
2. Passed over 30+ anti-crawling systems
Officially tested and proven to work with:
- Cloudflare Turnstile: Passed directly
- FingerprintJS: Not detected
- BrowserScan: Passed
- reCAPTCHA v3: Score of 0.9 (human-level performance)
In practice, CloakBrowser can easily handle Cloudflare’s 5-second verification pages.
3. Human behavior simulation
When humanize=True is enabled:
- Mouse movements follow a natural path (not straight lines)
- Keyboard inputs have natural pauses
- Scroll behavior mimics human behavior
This is very effective against behavior-based anti-crawling systems.
4. Perfect compatibility with Playwright/Puppeteer
The API is fully compatible; you just need to change the import statement:
# Before
from playwright.sync_api import sync_playwright
pw = sync_playwright().start()
browser = pw.chromium.launch()
# Now
from cloakbrowser import launch
browser = launch()The same goes for JavaScript:
import { launch } from 'cloakbrowser';
const browser = await launch();You can use CloakBrowser with your existing Playwright code with almost no modifications.
5. Built-in profile manager
CloakBrowser also comes with a Browser Profile Manager that can be self-hosted:
docker run -p 8080:8080 -v cloakprofiles:/data cloakhq/cloakbrowser-managerBy accessing localhost:8080, you can create different browser profiles, each with its own fingerprint and proxy settings. It’s similar to services like Multilogin or GoLogin, but it’s free and open-source.
Installation:
pip install cloakbrowser
# Or
npm install cloakbrowserUpon installation, Chromium binaries (about 200MB in size) will be downloaded and cached locally. You can also use Docker:
docker run --rm cloakhq/cloakbrowser cloaktestUse Cases:
Crawling bypass
This is the most direct use case. Many websites use anti-crawling measures like Cloudflare, and regular methods like requests or Selenium won’t work. CloakBrowser bypasses these restrictions, saving a lot of time.
Automated testing
Some websites’ anti-crawling systems may mistakenly block automated tests. Using CloakBrowser ensures that tests can run smoothly without being blocked.
Data collection
When collecting data from websites with anti-crawling protections, CloakBrowser is one of the most reliable solutions.
Usage Tips:
- Use with a residential proxy. Even with advanced fingerprint modification techniques, an IP from a data center can still be detected. A residential proxy combined with CloakBrowser is the best approach.
- Enable the
humanizemode. Unless you’re sure the target website doesn’t monitor behavior, it’s recommended to always use this mode. - Don’t switch fingerprints frequently. Use the same fingerprint for the entire session to avoid confusion.
- Stay up to date. Anti-crawling systems are constantly evolving, so it’s important to keep CloakBrowser’s patches up to date.
Summary:
CloakBrowser is one of the highest-quality open-source solutions for bypassing anti-crawling measures. Its C++-based modifications give it a natural advantage in combating such systems, and its compatibility with Playwright/Puppeteer makes the transition to using it very easy.
If you’re tired of dealing with Cloudflare’s anti-crawling measures, give CloakBrowser a try. It’s free and open-source, so there’s no reason not to use it.
GitHub: github.com/CloakHQ/CloakBrowser