What is this?

Every website you visit already sees a surprising amount about you — your IP address, rough location, browser and device details, screen size, installed fonts, timezone, and more. fst.st shows you that exact outside view: the same signals a server sees on any ordinary page load, laid out plainly instead of quietly logged. Nothing on this page is sent to fst.st's server or stored — every signal below is read and displayed locally in your browser.

Two sibling addresses let you test your own connectivity honestly: 4.fst.st only resolves and connects over IPv4, and 6.fst.st only resolves and connects over IPv6 — load either one to see whether you actually have working dual-stack internet, not just what your OS claims.