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ExplainerYahoo closes GeoCities: how the web lost millions of home pagesYahoo bought GeoCities for billions in 1999 and switched it off a decade later. The closure became a turning point for web preservation.ExplainerThe Storm worm: the botnet that started with a weather headlineIn January 2007 an email about deadly storms in Europe spread a Trojan that built one of the largest peer-to-peer botnets of its time.ExplainerGPLv3: how the free software licence was rewrittenAfter 18 months of public drafting, the Free Software Foundation published version 3 of the GNU General Public License in June 2007.ExplainerThe UK identity card scheme: from Act of Parliament to shredded registerBritain legislated for national ID cards backed by a central biometric register, then abolished the whole scheme within five years.ExplainerThe netbook era: small, cheap laptops that briefly drove PC growthThe Asus Eee PC started a boom in low-cost mini laptops that propped up PC sales, until tablets and thinner laptops took their place.

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What is my user agent?

This is the user agent string your browser sends with every request, and what it says about you. It is read and decoded in your browser. This page does not log or store it.

Reading your browser…

What a user agent string is

Every time your browser asks a website for a page, it sends a short line of text in the User-Agent header that names the software making the request. Sites use it for statistics, to work around bugs in particular browsers, and sometimes to offer the right download for your operating system.

Why it looks so strange

Almost every browser’s string starts with Mozilla/5.0, and Chrome claims to be Safari as well. This is history, not a mistake. In the 1990s some sites sent their best pages only to Netscape, whose code name was Mozilla, so other browsers began to claim to be “Mozilla compatible”. Each new browser then copied the tokens of the one before it so that it would not be locked out. The result is a string in which the useful parts are near the end.

Why your version number may look rounded

Browsers now send less detail than they used to, because a precise string helps sites track people across the web. Chrome, Edge and other Chromium browsers have frozen parts of the string: the operating system version is often fixed, for example Windows always shows as Windows NT 10.0 even on Windows 11, and only the major browser version is reliable. Safari likewise reports a fixed macOS version. Where your browser supports it, this page also reads the newer User-Agent Client Hints, which can give the real platform version, and shows them separately.

Can I change my user agent?

Yes. Chrome, Edge and Firefox can override it from their developer tools, and extensions exist for permanent changes. Changing it rarely improves privacy, though: an unusual string can make you easier to pick out, not harder. Mozilla’s User-Agent reference explains the format in detail.