Device fingerprint

A device fingerprint is an identifier built from the characteristics a browser or app exposes — screen size, installed fonts, time zone, language, graphics hardware, and dozens more — which together are distinctive enough to recognize the same device again later. No cookie is involved, so clearing storage does not reset it.

Why it matters when you buy proxies

This is the single most common reason a proxy purchase disappoints. A proxy changes the address your traffic comes from and nothing else. If the same browser profile visits a site through five different IPs, the fingerprint underneath is identical every time, and the site can link all five sessions to one machine — which looks stranger than never having used a proxy at all.

A good address and a repeated fingerprint is a worse combination than a mediocre address and clean separation. Both halves have to change together.

What actually separates identities

• A separate browser profile per identity, so cookies, storage and the exposed traits are not shared. Antidetect browsers exist to automate this.
• A consistent story. A time zone that contradicts the IP's location is its own signal, so the profile and the address should agree.
• Separate hardware where it matters most — a real handset has real sensors and a real IMEI rather than values a browser reports about itself.

A concrete example

Ten accounts opened in ten tabs of one browser, each tab on its own mobile proxy, still read as one device to any site that fingerprints. Ten separate profiles, each pinned to one address, read as ten.