Paste a user agent string, or load the current browser's string, to break it down into browser, engine, operating system and device type.
The parser matches the well-known tokens in a user agent string in a deliberate order — Edge and Opera tokens appear inside strings that also contain the Chrome token, so they are checked first, and Safari is recognised by its Version token. Device type is estimated from tokens such as Mobile, Tablet and iPad. Modern browsers freeze or reduce their user agent strings to limit fingerprinting, freezing the version and platform details, so results are approximate: a recent Chrome string, for example, may report a fixed operating system version that is not the real one.
Why does the operating system version look wrong for a recent browser? Modern browsers freeze or reduce parts of the user agent string to limit fingerprinting, so the platform and version tokens may be fixed placeholders rather than the real values. The parse reflects what the string says, not necessarily the device.
Why does an Edge string also contain Chrome and Safari tokens? For historical compatibility, most browsers claim to be Mozilla and include tokens for engines they resemble. The distinctive token (Edg, OPR, SamsungBrowser) is the one that identifies the actual browser, which is why parsing order matters.
Is the current browser's user agent sent anywhere? No. The button copies navigator.userAgent from the browser into the box locally, and parsing happens on the page.