Browser
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Engine
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Operating system
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Device
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About this tool
A user agent (UA) string is the self-reported identifier a browser or HTTP client sends in the User-Agent request header. It packs the browser name and version, the rendering engine (Blink, Gecko or WebKit), the operating system and often the device model into one terse, historically messy line. This parser runs a regex cascade over that string where order matters: bots and Chromium forks like Edge, Opera and Samsung Internet are matched before the generic Chrome and Safari tokens they all impersonate, so each UA resolves to a single, correct answer.
Use it to debug why a request is being served the wrong layout, confirm what a crawler such as Googlebot or AhrefsBot reports, sanity-check analytics that bucket traffic by device type, or read the frozen macOS 10.15.7 and Windows NT 10.0 values that Apple and Microsoft never bump. Paste a string from your logs, or click "Use my user agent" to inspect the browser you are reading this in, and copy the parsed JSON straight into a test fixture or bug report.
User agent strings are self-reported and trivially spoofed, so treat parsed results as a hint, not a security control or proof of identity.
Frequently asked questions
How do I find my own browser's user agent string?
Your browser exposes it as navigator.userAgent in the JavaScript console, and this tool's "Use my user agent" button fills it in for you. It is also sent in the User-Agent header of every HTTP request your browser makes.
Why does Safari on macOS report version 10.15.7 even on newer systems?
Apple froze the macOS version Safari reports at 10_15_7 to reduce fingerprinting, so the OS number in the UA string no longer tracks the real system version. Microsoft did the same by keeping Windows 11 on the Windows NT 10.0 token used by Windows 10.
What is the difference between the browser and the rendering engine?
The browser is the application (Chrome, Edge, Firefox, Safari), while the engine is the component that parses HTML and CSS and paints the page. Chrome and every Chromium fork use Blink, Firefox uses Gecko, and Safari plus all iOS browsers use WebKit.