How Do Websites Know You're Using a Tool?

Modern websites use a technique called 'browser fingerprinting' to identify and track users, as well as to detect automation behaviors.

Every browser leaves a unique trace.

A browser fingerprint is a collection of information that your browser automatically provides to a website. When combined, this information can create a nearly unique 'identity' for you, even without using cookies.

Information That is Collected

• User Agent: A text string indicating the browser name, version, and operating system.
• Hardware parameters: Screen resolution, number of CPU cores, amount of RAM.
• Software parameters: List of installed fonts, browser plugins.
• Network information: Time zone, language, and WebRTC leaks that can reveal your real IP address.
• Canvas Fingerprinting: A technique that asks the browser to draw a hidden image. Minor differences in graphics cards and drivers will produce slightly different images, creating a powerful identifier.

How Automation Tools are Detected

Automation tools like Selenium are often detected because they create unnatural or inconsistent fingerprints.

• Mismatched parameters: For example, the User Agent says Windows but the font list is from macOS.
• Lack of natural parameters: An automated browser might lack information about the battery, motion sensors, etc., that a real device has.
• Non-human behavior: Moving the mouse in a straight line, typing too fast and evenly, or navigating between pages instantly.

This is precisely why antidetect browsers were created. They not only change these parameters but also strive to create fingerprint sets that look identical to those of real users, helping to bypass sophisticated detection systems.

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