What Is My User Agent?

A user agent is a string of text that your browser sends to web servers identifying itself. It typically includes the browser name and version, operating system, rendering engine, and sometimes device information.

Yes, your user agent string is sent with every HTTP request. Any website you visit can read it. This is by design — it helps websites serve compatible content for your browser and device.

Yes, you can change your user agent using browser developer tools, browser extensions, or settings. This is called user agent spoofing. It's commonly used for testing how websites appear on different browsers or devices.

User agent strings grew complicated over browser history. Each new browser added compatibility tokens from older browsers so websites wouldn't block them. For example, most browsers still include "Mozilla/5.0" for historical reasons.

Your user agent is one piece of information your browser shares. A browser fingerprint combines many data points — screen size, fonts, plugins, WebGL info, and more — to create a unique identifier. The user agent alone is not unique enough to track you.