<h3 align="center">Stealth Chromium that passes every bot detection test.</h3>
<table><tr><td>
Not a patched config. Not a JS injection. A real Chromium binary with fingerprints modified at the C++ source level. Antibot systems score it as a normal browser — because it <em>is</em> a normal browser.
- **Timezone & locale from proxy IP** — `launch(proxy="...", geoip=True)` auto-detects timezone and locale
- **Playwright + Puppeteer from one package** — `import from 'cloakbrowser'` or `import from 'cloakbrowser/puppeteer'`. Same binary, your choice of API
- **Persistent profiles** — `launch_persistent_context()` keeps cookies and localStorage across sessions, bypasses incognito detection
- **Config-level patches break** — `playwright-stealth`, `undetected-chromedriver`, and `puppeteer-extra` inject JavaScript or tweak flags. Every Chrome update breaks them. Antibot systems detect the patches themselves.
- **CloakBrowser patches Chromium source code** — fingerprints are modified at the C++ level, compiled into the binary. Detection sites see a real browser because it *is* a real browser.
- **Source-level stealth** — C++ patches handle fingerprints (GPU, screen, UA, hardware reporting) at the binary level. No JavaScript injection, no config-level hacks. Most stealth tools only patch at the surface.
- **Works with any browser automation framework** — tested and passing stealth checks with Playwright, Puppeteer, Selenium, undetected-chromedriver, browser-use, Crawl4AI, and agent-browser. Just point any Chromium-based framework at the binary path.
CloakBrowser doesn't solve CAPTCHAs — it prevents them from appearing. No CAPTCHA-solving services, no proxy rotation built in — bring your own proxies, use the Playwright API you already know.
The binary includes 26 source-level patches covering canvas, WebGL, audio, fonts, GPU, screen properties, hardware reporting, and automation signal removal.
Same as `launch_context()`, but with a persistent user profile. Cookies, localStorage, and cache persist across sessions. Also avoids incognito detection by services like BrowserScan.
> **Note:** The Playwright wrapper is recommended for sites with reCAPTCHA Enterprise. Puppeteer's CDP protocol leaks automation signals that reCAPTCHA Enterprise can detect, causing intermittent 403 errors. This is a known Puppeteer limitation, not specific to CloakBrowser. Use Playwright for best results.
The binary is **stealthy by default** — no flags needed. It auto-generates a random fingerprint seed at startup and spoofs all detectable values (GPU, hardware specs, screen dimensions, canvas, WebGL, audio, fonts). Every launch produces a fresh, coherent identity.
**How fingerprinting works:**
| Scenario | What happens |
|----------|-------------|
| **No flags** | Random seed auto-generated at startup. GPU, screen, hardware specs, and all noise patches are spoofed automatically. Fresh identity each launch. |
| **`--fingerprint=seed`** | Deterministic identity from the seed. Same seed = same fingerprint across launches. Use this for session persistence (returning visitor). |
| **`--fingerprint=seed` + explicit flags** | Explicit flags override individual auto-generated values. The seed fills in everything else. |
The binary detects its platform at compile time — a macOS binary reports as macOS with Apple GPU, a Linux binary reports as Linux with NVIDIA GPU. The **wrapper** overrides this on Linux by passing `--fingerprint-platform=windows`, so sessions appear as Windows desktops (more common fingerprint, harder to cluster). Use `--fingerprint-platform` for cross-platform spoofing when running the binary directly.
> **Tip: Use a fixed seed when revisiting the same site.** A random seed makes every session look like a different device — which can be suspicious when hitting the same site repeatedly from the same IP. For reCAPTCHA v3 Enterprise and similar scoring systems, a fixed seed produces a consistent fingerprint across sessions, making you look like a returning visitor:
Every `launch()` call sets these automatically. The **wrapper** applies platform-aware defaults — on Linux it spoofs as Windows for a more common fingerprint, on macOS it runs as a native Mac browser:
The binary auto-generates hardware concurrency (8), device memory (8), and screen dimensions (1920x1080 on Windows/Linux, 1440x900 on macOS) from the seed. Override with explicit flags if needed.
> **Using the binary directly?** It works out of the box with zero flags — the binary auto-spoofs everything. Pass `--fingerprint=seed` for a persistent identity, or use explicit flags like `--fingerprint-gpu-renderer` to override any auto-generated value.
> **Production tip:** For better stealth at scale, pass your own GPU, screen, and hardware values instead of relying on defaults. Custom parameters make your sessions harder to cluster by anti-bot systems that look for uniform fingerprint profiles.
> **Note:** All stealth tests were verified with the default fingerprint config above. Changing these flags may affect detection results — test your configuration before using in production.
### Examples
```python
# Pin a seed for a persistent identity
browser=launch(args=["--fingerprint=42069"])
# Full control — disable defaults, set everything yourself
**macOS first launch:** The binary is ad-hoc signed. On first run, macOS Gatekeeper will block it. Right-click the app → **Open** → click **Open** in the dialog. This is only needed once.
This runs a real headed browser rendered on a virtual display — no physical monitor needed. Combined with a residential proxy, this passes even the most aggressive detection services. Datacenter IPs are often flagged by IP reputation regardless of browser fingerprint — a residential proxy makes the difference.
Some sites challenge first-time visitors with no cookies over HTTP/2. This affects all Chromium browsers, not just CloakBrowser. Use a persistent profile to warm up cookies once, then reuse across sessions:
For stateless/ephemeral use cases, `launch(args=["--disable-http2"])` forces HTTP/1.1 which bypasses the check. Only use this flag for sites that require it — most work fine with HTTP/2.
**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:
**macOS: Blocked on some sites that pass on Linux**
The macOS fingerprint profile has known inconsistencies that aggressive bot detection catches. If a site blocks you on macOS but works on Linux, switch to a Windows fingerprint profile by passing `stealth_args=False` and manually setting `--fingerprint-platform=windows` with matching GPU flags (see [Fingerprint Management](#fingerprint-management) for the full flag list).
By default, `launch()` opens an incognito context. Some sites (like BrowserScan) detect this. Use `launch_persistent_context()` instead — it runs with a real user profile, so incognito detection passes:
- **Try the Patchright backend** — suppresses CDP automation signals that reCAPTCHA Enterprise detects. Install with `pip install cloakbrowser[patchright]`, then use `launch(backend="patchright")` or set `CLOAKBROWSER_BACKEND=patchright` globally. Note: Patchright breaks proxy auth and `add_init_script` — only use it when you need the extra CDP stealth
- **Use Playwright, not Puppeteer** — Puppeteer sends more CDP protocol traffic that reCAPTCHA detects ([details](#puppeteer))
- **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 `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:
```python
page.type("#email", "user@example.com", delay=50)
```
- **Minimize `page.evaluate()` calls** before the reCAPTCHA check fires — each one sends CDP traffic
A: CloakBrowser is a browser built on open-source Chromium. We do not condone illegal use. Automating systems without authorization, credential stuffing, and account creation abuse are expressly prohibited. See [BINARY-LICENSE.md](https://github.com/CloakHQ/CloakBrowser/blob/main/BINARY-LICENSE.md) for full terms.
A: Camoufox patches Firefox. We patch Chromium. Chromium means native Playwright support, larger ecosystem, and TLS fingerprints that match real Chrome. Camoufox returned in early 2026 but is in unstable beta — CloakBrowser is production-ready.
**Q: Will detection sites eventually catch this?**
A: Possibly. Bot detection is an arms race. Source-level patches are harder to detect than config-level patches, but not impossible. We actively monitor and update when detection evolves.
**Q: Can I use my own proxy?**
A: Yes. Pass `proxy="http://user:pass@host:port"` to `launch()`.
- **Wrapper code** (this repository) — MIT. See [LICENSE](https://github.com/CloakHQ/CloakBrowser/blob/main/LICENSE).
- **CloakBrowser binary** (compiled Chromium) — free to use, no redistribution. See [BINARY-LICENSE.md](https://github.com/CloakHQ/CloakBrowser/blob/main/BINARY-LICENSE.md).
