Example: Stealth Mode

See what stealth mode changes by comparing fingerprint signals with stealth on and off.

Code

import asyncio
import json

from voidcrawl import BrowserConfig, BrowserSession, Page

DETECTION_JS = """
JSON.stringify({
    webdriver: navigator.webdriver,
    plugins_count: navigator.plugins.length,
    languages: navigator.languages,
    has_chrome_runtime: typeof window.chrome !== 'undefined'
        && typeof window.chrome.runtime !== 'undefined',
})
"""


async def check_fingerprint(label: str, page: Page) -> None:
    raw = await page.evaluate_js(DETECTION_JS)
    fingerprint = json.loads(raw)
    print(f"\n[{label}]")
    for key, value in fingerprint.items():
        print(f"  {key}: {value}")


async def main() -> None:
    # Stealth ON (default)
    async with BrowserSession(BrowserConfig(stealth=True)) as browser:
        page = await browser.new_page("https://qscrape.dev")
        await check_fingerprint("stealth=True", page)
        await page.close()

    # Stealth OFF
    async with BrowserSession(BrowserConfig(stealth=False)) as browser:
        page = await browser.new_page("https://qscrape.dev")
        await check_fingerprint("stealth=False", page)
        await page.close()


if __name__ == "__main__":
    asyncio.run(main())

What to Look For

Signal	Stealth ON	Stealth OFF
navigator.webdriver	undefined or None	True
plugins_count	> 0 (real plugins)	> 0 (real plugins)
languages	Realistic list	Realistic list
has_chrome_runtime	True	True

The key difference is navigator.webdriver. With stealth on, it’s removed from the prototype chain. With stealth off, Chrome sets it to true, which is the primary signal WAFs check.

See the Stealth Mode guide for the full explanation of what’s patched and why.