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.

• 48 source-level C++ patches — canvas, WebGL, audio, fonts, GPU, screen, WebRTC, network timing, 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 — tested with browser-use, Crawl4AI, Scrapling, Stagehand (example), LangChain, Selenium, and more

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 (HTTP or SOCKS5)
const browser = await launch({
  proxy: 'http://user:pass@proxy:8080',
});
const browser = await launch({
  proxy: 'socks5://user:pass@proxy:1080',
});

// 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
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 via binary flags)
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.

CLI

Pre-download the binary or check installation status from the command line:

npx cloakbrowser install      # Download binary with progress output
npx cloakbrowser info         # Show version, path, platform
npx cloakbrowser update       # Check for and download newer binary
npx cloakbrowser clear-cache  # Remove cached binaries

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 | 48 | ✅ Latest | | Linux arm64 (RPi, Graviton) | 145 | 48 | ✅ Latest | | macOS arm64 (Apple Silicon) | 145 | 26 | ✅ Latest | | macOS x86_64 (Intel) | 145 | 26 | ✅ Latest | | Windows x86_64 | 145 | 48 | ✅ Latest |

Requirements

• Node.js >= 20
• 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', '[email protected]', { 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-145.0.7632.159.2/chrome

# macOS
export CLOAKBROWSER_BINARY_PATH=~/.cloakbrowser/chromium-145.0.7632.109.2/Chromium.app/Contents/MacOS/Chromium

# Windows
set CLOAKBROWSER_BINARY_PATH=%USERPROFILE%\.cloakbrowser\chromium-145.0.7632.159.7\chrome.exe

Links

• 🌐 Website
• 🐛 Bug reports & feature requests
• 📦 PyPI (Python package)
• 📖 Full documentation
• 📧 Contact: [email protected]

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.