Parser User-Agent

What the User-Agent Parser does

Every HTTP request your browser makes includes a User-Agent header, a single dense string that claims which browser, engine, operating system and device you are using. The User-Agent Parser takes any such string, whether you paste one in or press "Use mine" to read your own, and decodes it into plain facts: the browser and version, the rendering engine, the operating system and version, the device type, and whether the string looks like a bot. A modern example such as Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0 Safari/537.36 comes back parsed as Chrome 126, Blink engine, Windows 10/11, Desktop, not a bot.

How the parsing works

Behind the scenes the tool applies an ordered set of pattern matches, and the order matters a great deal because User-Agent strings are famously misleading. Almost every browser still begins with Mozilla/5.0 for historical compatibility, and Chromium-based browsers deliberately include the words "Chrome" and "Safari" even when they are neither. So the parser checks for the more specific tokens first, such as Edg for Edge, OPR for Opera, YaBrowser for Yandex and SamsungBrowser for Samsung Internet, before falling back to Firefox, then Chrome, then Safari, so that a Microsoft Edge string is never mistaken for plain Chrome. Operating-system detection reads markers like Windows NT 10.0, Android 14, iPhone OS 17_5 or Mac OS X 14_5 (converting the underscores back to dots), and the engine is inferred from Gecko, from AppleWebKit with Chrome (Blink), from plain WebKit, or from Trident. Device type is guessed from mobile and tablet keywords, and an extra check flags common crawler and headless signatures.

When it is handy

• Making sense of web-server or application logs where raw User-Agent strings are unreadable at a glance.
• Reproducing a bug a user reported by pinning down their exact browser, version and platform.
• Spotting bots and headless automation hitting your site.
• Checking what your own browser quietly announces about you to every site you visit.

Tips and gotchas

Treat the User-Agent as a claim, not a fact: it is trivially editable, so any value can be spoofed and bots routinely impersonate real browsers, which is why the "likely bot" flag is a hint rather than proof. The header is also being deliberately wound down; browsers now freeze and simplify it, shifting the real detail into User-Agent Client Hints that are sent separately and only on request, so very new browsers may report less precise versions here. Even so, your genuine User-Agent is a meaningful strand of your device fingerprint, and an unusual or outdated string makes you stand out in a crowd. Because it travels with every request regardless of your network, changing your IP address does not change it. To see the network half of your identity, the address and location a site records, pair this with our IP check.

Parsed entirely in your browser

Whatever string you enter is analysed locally by the JavaScript on this page. Nothing is sent to a server, nothing is stored and nothing is logged; "Use mine" simply reads the value your own browser already exposes, and Copy writes only to your clipboard. A User-Agent can hint at your whole setup, so the right place to inspect one is on your own device, which is exactly where this tool keeps it.