CloakBrowser/js

CloakBrowser

Stealth Chromium that passes every bot detection test.

Drop-in Playwright/Puppeteer replacement. Same API, same code — just swap the import. 3 lines of code, 30 seconds to unblock.

• 26 source-level C++ patches — canvas, WebGL, audio, fonts, GPU, screen, automation signals
• 0.9 reCAPTCHA v3 score — human-level, server-verified
• Passes Cloudflare Turnstile, FingerprintJS, BrowserScan — tested against 30+ detection sites
• npm install cloakbrowser — binary auto-downloads, auto-updates, zero config
• Free and open source — no subscriptions, no usage limits
• Works with any framework — also tested with Selenium, undetected-chromedriver, browser-use, Crawl4AI, and agent-browser

Install

# With Playwright
npm install cloakbrowser playwright-core

# With Puppeteer
npm install cloakbrowser puppeteer-core

On first launch, the stealth Chromium binary auto-downloads (~200MB, cached at ~/.cloakbrowser/).

Usage

Playwright (default)

import { launch } from 'cloakbrowser';

const browser = await launch();
const page = await browser.newPage();
await page.goto('https://protected-site.com');
console.log(await page.title());
await browser.close();

Puppeteer

Note: Playwright is recommended for sites with reCAPTCHA Enterprise. Puppeteer's CDP protocol leaks automation signals that reCAPTCHA Enterprise can detect. This is a known Puppeteer limitation, not specific to CloakBrowser.

import { launch } from 'cloakbrowser/puppeteer';

const browser = await launch();
const page = await browser.newPage();
await page.goto('https://protected-site.com');
console.log(await page.title());
await browser.close();

Options

import { launch, launchContext, launchPersistentContext } from 'cloakbrowser';

// With proxy
const browser = await launch({
  proxy: 'http://user:pass@proxy:8080',
});

// With proxy object (bypass, separate auth fields)
const browser = await launch({
  proxy: { server: 'http://proxy:8080', bypass: '.google.com', username: 'user', password: 'pass' },
});

// Headed mode (visible browser window)
const browser = await launch({ headless: false });

// Extra Chrome args
const browser = await launch({
  args: ['--fingerprint=12345'],
});

// With timezone and locale (sets --fingerprint-timezone and --lang binary flags)
const browser = await launch({
  timezone: 'America/New_York',
  locale: 'en-US',
});

// Auto-detect timezone/locale from proxy IP (requires: npm install mmdb-lib)
const browser = await launch({
  proxy: 'http://proxy:8080',
  geoip: true,
});

// Browser + context in one call (timezone/locale set both binary flags AND context)
const context = await launchContext({
  userAgent: 'Custom UA',
  viewport: { width: 1920, height: 1080 },
  locale: 'en-US',
  timezone: 'America/New_York',
});

// Persistent profile — stay logged in, bypass incognito detection, load extensions
const ctx = await launchPersistentContext({
  userDataDir: './chrome-profile',
  headless: false,
  proxy: 'http://user:pass@proxy:8080',
});
const page = ctx.pages()[0] || await ctx.newPage();
await page.goto('https://example.com');
await ctx.close();  // profile saved — reuse same path to restore state

Auto Timezone/Locale from Proxy IP

When using a proxy, antibot systems check that your browser's timezone and locale match the proxy's location. Install mmdb-lib to enable auto-detection from an offline GeoIP database (~70 MB, downloaded on first use):

npm install mmdb-lib

// Auto-detect — timezone and locale set from proxy's IP geolocation
const browser = await launch({ proxy: 'http://proxy:8080', geoip: true });

// Works with launchContext too
const context = await launchContext({ proxy: 'http://proxy:8080', geoip: true });

// Explicit values always win over auto-detection
const browser = await launch({ proxy: 'http://proxy:8080', geoip: true, timezone: 'Europe/London' });

Note: For rotating residential proxies, the DNS-resolved IP may differ from the exit IP. Pass explicit timezone/locale in those cases.

Utilities

import { ensureBinary, clearCache, binaryInfo, checkForUpdate } from 'cloakbrowser';

// Pre-download binary (e.g., during Docker build)
await ensureBinary();

// Check installation
console.log(binaryInfo());

// Force re-download
clearCache();

// Manually check for newer Chromium version
const newVersion = await checkForUpdate();
if (newVersion) console.log(`Updated to ${newVersion}`);

Test Results

Detection Service	Stock Browser	CloakBrowser
reCAPTCHA v3	0.1 (bot)	0.9 (human)
Cloudflare Turnstile	FAIL	PASS
FingerprintJS	DETECTED	PASS
BrowserScan	DETECTED	NORMAL (4/4)
bot.incolumitas.com	13 fails	1 fail
navigator.webdriver	true	false
CDP detection	Detected	Not detected
TLS fingerprint	Mismatch	Identical to Chrome
		Tested against 30+ detection sites

Configuration

Env Variable	Default	Description
CLOAKBROWSER_BINARY_PATH	—	Skip download, use a local Chromium binary
CLOAKBROWSER_CACHE_DIR	~/.cloakbrowser	Binary cache directory
CLOAKBROWSER_DOWNLOAD_URL	cloakbrowser.dev	Custom download URL
CLOAKBROWSER_AUTO_UPDATE	true	Set to false to disable background update checks
CLOAKBROWSER_SKIP_CHECKSUM	false	Set to true to skip SHA-256 verification after download

Migrate From Playwright

- import { chromium } from 'playwright';
- const browser = await chromium.launch();
+ import { launch } from 'cloakbrowser';
+ const browser = await launch();

const page = await browser.newPage();
// ... rest of your code works unchanged

Platforms

Platform	Chromium	Patches	Status
Linux x86_64	145	26	✅ Latest
macOS arm64 (Apple Silicon)	145	26	✅ Latest
macOS x86_64 (Intel)	145	26	✅ Latest
Windows x86_64	145	26	✅ Latest

Requirements

• Node.js >= 18
• One of: playwright-core >= 1.40 or puppeteer-core >= 21

Troubleshooting

Site detects incognito / private browsing mode

By default, launch() opens an incognito context. Some sites (like BrowserScan) detect this. Use launchPersistentContext() instead — it runs with a real user profile:

import { launchPersistentContext } from 'cloakbrowser';

const ctx = await launchPersistentContext({
  userDataDir: './my-profile',
  headless: false,
});

This also gives you cookie and localStorage persistence across sessions.

reCAPTCHA v3 scores are low (0.1–0.3)

Avoid page.waitForTimeout() — it sends CDP protocol commands that reCAPTCHA detects. Use native sleep instead:

// Bad — sends CDP commands, reCAPTCHA detects this
await page.waitForTimeout(3000);

// Good — invisible to the browser
await new Promise(r => setTimeout(r, 3000));

Other tips for maximizing reCAPTCHA scores:

• Use Playwright, not Puppeteer — Puppeteer sends more CDP protocol traffic that reCAPTCHA detects (details)
• Use residential proxies — datacenter IPs are flagged by IP reputation, not browser fingerprint
• Spend 15+ seconds on the page before triggering reCAPTCHA — short visits score lower
• Space out requests — back-to-back grecaptcha.execute() calls from the same session get penalized. Wait 30+ seconds between pages with reCAPTCHA
• Use a fixed fingerprint seed (--fingerprint=12345) for consistent device identity across sessions
• Use page.type() instead of page.fill() for form filling — fill() sets values directly without keyboard events, which reCAPTCHA's behavioral analysis flags. type() with a delay simulates real keystrokes:

  await page.type('#email', 'user@example.com', { delay: 50 });
  

• Minimize page.evaluate() calls before the reCAPTCHA check fires — each one sends CDP traffic

New update broke something? Roll back to the previous version When auto-update downloads a newer binary, the previous version stays in ~/.cloakbrowser/. Point CLOAKBROWSER_BINARY_PATH to the older cached binary:

# Linux
export CLOAKBROWSER_BINARY_PATH=~/.cloakbrowser/chromium-145.0.7632.109/chrome

# macOS
export CLOAKBROWSER_BINARY_PATH=~/.cloakbrowser/chromium-145.0.7632.109/Chromium.app/Contents/MacOS/Chromium

# Windows
set CLOAKBROWSER_BINARY_PATH=%USERPROFILE%\.cloakbrowser\chromium-145.0.7632.109\chrome.exe

Links

• 🌐 Website
• 🐛 Bug reports & feature requests
• 📦 PyPI (Python package)
• 📖 Full documentation
• 📧 Contact: cloakhq@pm.me

License

• Wrapper code (this repository) — MIT. See LICENSE.
• CloakBrowser binary (compiled Chromium) — free to use, no redistribution. See BINARY-LICENSE.md.

Use against financial, banking, healthcare, or government authentication systems without authorization is expressly prohibited.