my browser user agent
The User-Agent is a single text string the browser sends on every HTTP request and also exposes via `navigator.userAgent`, but it is in the middle of a deliberate reduction process: Chromium-based browsers have been stripping version and operating system detail out of that string and moving that information to a separate API, Client Hints. This page shows your current User-Agent and explains why it no longer tells the whole story on its own.
The `Windows NT 10.0` token does not tell Windows 10 apart from Windows 11 in this browser: UA reduction flattens both versions into the same generic value on purpose.
Safari keeps the `Version/17.0` token separate from the WebKit build number, and it does not expose `navigator.userAgentData`, so Client Hints detection does not work in this browser.
The `rv:121.0` token repeats the Firefox version on purpose, an old practice to stay compatible with scripts that only read that field instead of the `Firefox/` token.
User-Agent is a string sent by the browser in HTTP requests and exposed via JavaScript. It usually includes browser, engine, operating system and historical compatibility tokens.
Because `Mozilla/5.0` became a historical compatibility token every modern browser keeps at the start of the string, with no relation at all to the current Mozilla/Firefox browser; older sites checked that prefix to decide whether to unlock advanced content, and dropping it would break those legacy checks.
It is the effort, led by Chrome since 2021, to strip detailed operating system and device version information out of the traditional User-Agent, replacing specific values with generic, frozen tokens; the stated motivation is reducing the signals sites can use to identify a browser without cookies.
No: this Client Hints API only exists on Chromium-based browsers, such as Chrome, Edge and Opera; Firefox and Safari do not implement `navigator.userAgentData`, so any code that depends on it exclusively needs a fallback path based on `navigator.userAgent` for those two browsers.
It is not recommended: the User-Agent can be changed manually by the user or by an extension, is already being deliberately reduced by browsers themselves, and never guarantees a specific API actually exists in that browser; checking the API itself with `'apiName' in object` is always more reliable than parsing the string.
Reading happens locally and does not send User-Agent, timezone or capabilities to analytics.