ManagedCode.Playwright.Stealth (.NET)

ManagedCode.Playwright.Stealth applies a curated set of init scripts to Microsoft.Playwright contexts to reduce common bot-detection signals. It adapts the original playwright_stealth scripts for .NET with ManagedCode conventions.

Install

dotnet add package ManagedCode.Playwright.Stealth

Quick Start

using Microsoft.Playwright;
using ManagedCode.Playwright.Stealth;

using var playwright = await Playwright.CreateAsync();
await using var browser = await playwright.Chromium.LaunchAsync(new BrowserTypeLaunchOptions
{
    Headless = true
});

var context = await browser.NewContextAsync();

// Apply ManagedCode.Playwright.Stealth before creating pages.
await context.ApplyStealthAsync();

var page = await context.NewPageAsync();
await page.GotoAsync("https://www.browserscan.net/bot-detection");

Configuration

var config = new StealthConfig
{
    NavigatorHardwareConcurrency = 8,
    NavigatorLanguages = true,
    NavigatorUserAgentValue = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
    WebglVendor = true
};

// Apply ManagedCode.Playwright.Stealth with a custom config.
await context.ApplyStealthAsync(config);

Usage Variants (C#/.NET)

Apply stealth on a page (if you already have a page instance):

var page = await context.NewPageAsync();

// Apply ManagedCode.Playwright.Stealth to an existing page.
await page.ApplyStealthAsync();

await page.GotoAsync("https://www.browserscan.net/bot-detection");

Disable individual patches:

var config = new StealthConfig
{
    WebDriver = false,
    WebglVendor = false,
    NavigatorLanguages = false,
    NavigatorPlugins = false,
    ChromeRuntime = false
};

// Apply ManagedCode.Playwright.Stealth with selective patches disabled.
await context.ApplyStealthAsync(config);

Customize platform, vendor, and WebGL identity:

var config = new StealthConfig
{
    NavigatorPlatformValue = "Win32",
    NavigatorVendorValue = "Google Inc.",
    NavigatorUserAgentValue = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
    Vendor = "Intel Inc.",
    Renderer = "Intel Iris OpenGL Engine",
    Languages = new[] { "en-US", "en" },
    NavigatorHardwareConcurrency = 8
};

// Apply ManagedCode.Playwright.Stealth with explicit platform and WebGL identity.
await context.ApplyStealthAsync(config);

Run on insecure origins (affects chrome.runtime behavior):

var config = new StealthConfig
{
    RunOnInsecureOrigins = true
};

// Apply ManagedCode.Playwright.Stealth on insecure origins.
await context.ApplyStealthAsync(config);

Patched Signals

The default configuration applies patches for:

• navigator.webdriver
• navigator.plugins and navigator.mimeTypes
• navigator.languages
• navigator.userAgent
• navigator.vendor
• navigator.platform
• navigator.hardwareConcurrency
• window.chrome / chrome.runtime / related Chrome APIs
• WebGL vendor/renderer
• window.outerWidth / window.outerHeight
• media codecs and hairline fixes
• iframe contentWindow quirks

Configuration Reference

Common options in StealthConfig:

• WebDriver, WebglVendor, ChromeApp, ChromeCsi, ChromeLoadTimes, ChromeRuntime
• IframeContentWindow, MediaCodecs, Hairline, OuterDimensions
• NavigatorLanguages, NavigatorPermissions, NavigatorPlatform, NavigatorPlugins, NavigatorUserAgent, NavigatorVendor
• NavigatorHardwareConcurrency, NavigatorUserAgentValue, NavigatorPlatformValue, NavigatorVendorValue
• Vendor, Renderer, Languages, RunOnInsecureOrigins

Testing

Integration tests target these bot-detection sites:

• https://www.browserscan.net/bot-detection
• https://bot.sannysoft.com/
• https://www.intoli.com/blog/not-possible-to-block-chrome-headless/chrome-headless-test.html
• https://fingerprint.com/demo
• https://arh.antoinevastel.com/bots/areyouheadless/
• https://pixelscan.net/bot-check

These sites can change at any time. If a site changes, update the corresponding test assertions.

Run tests (Playwright browsers install automatically on first run):

dotnet test --solution ManagedCode.Playwright.Stealth.slnx -c Release

On Linux CI runners, set PLAYWRIGHT_INSTALL_DEPS=1 to install system dependencies (playwright install --with-deps) when tests start.

Google search verification is optional (Google may block automated traffic). Enable it with:

RUN_GOOGLE_SEARCH_TESTS=1 dotnet test --solution ManagedCode.Playwright.Stealth.slnx -c Release

Attribution

This project uses code from the original playwright_stealth repository and adapts it for .NET: https://github.com/AtuboDad/playwright_stealth

License

MIT. See LICENSE.