User Agent Viewer

A user agent string is a short line of text your browser sends with nearly every request, historically used by servers to decide what content or layout to serve. It typically bundles the browser name and version, the underlying rendering engine, and the operating system into one string — for example a string can indicate Chrome running on Windows while also containing 'Mozilla/5.0' and 'AppleWebKit', leftovers from decades of browsers claiming compatibility with earlier engines so that servers wouldn't block them.

This tool is useful for confirming exactly what a browser reports before troubleshooting a rendering issue, checking whether a browser update actually took effect, or verifying the user agent your device sends when testing how a site treats mobile versus desktop visitors. The parsed browser, OS and device type are derived by matching known patterns in the string, so unusual or very new browsers may be labeled generically or misidentified.

It's worth knowing that a user agent string can be changed freely — through browser developer tools, extensions, or by any script making a request — so it should never be treated as a reliable way to verify who or what is really making a request. Modern browsers are also moving toward sending less detail in the user agent by default (a shift often called User-Agent Reduction) and exposing finer-grained information only on request through the User-Agent Client Hints API, so raw user agent strings are gradually becoming less descriptive over time.