Browser Fingerprinting

Browser fingerprinting identifies or groups clients by observable browser and device characteristics beyond their IP address. A fingerprint can remain recognizable after the source IP changes because it is built from properties exposed by the client itself.

Signals can include the User-Agent, language, time zone, screen dimensions, available fonts, graphics output, audio processing, supported browser features, and the order or values of request headers. No single signal needs to be unique. A service can combine many ordinary characteristics into a profile that distinguishes one client or detects a combination that does not match a normal browser.

Fingerprinting can support fraud prevention, account security, analytics, and bot detection. It also has privacy implications because passive collection may be difficult for a visitor to notice or control. Modern browsers limit or standardize some high-entropy properties, but they cannot make every device and execution environment identical.

A proxy changes the network source address visible to a destination. It does not automatically change browser APIs, cookies, TLS behavior, or application state. This is why a residential proxy alone does not guarantee anonymity or make automation look like an ordinary browser. Read whether a residential proxy can be detected for related signals.

Related terms: User-Agent and TLS fingerprinting.