User Agent Finder
See what your browser and device report to every website you visit.
How to Use the User Agent Finder
- Load Inspector: Open the utility to dynamically read your HTTP User-Agent request header string.
- Analyze Specs: Breakdown browser engine, version, operating system, and device type.
- Copy String: Click "Copy Raw UA" to troubleshoot compatibility bugs or test API requests.
Why Use This Tool
Checking your browser's user agent string online for free reveals exactly what your browser and device report to every website you visit. This tool shows your current user agent string on both mobile and desktop, breaking it down into readable browser, OS, and device details. It gives an instant, no-setup way to confirm exactly what information a browser is broadcasting to every site visited.
How It Works
This user agent string checker and browser signature detector parses the navigator.userAgent property that your browser automatically sends with every web request, extracting the browser name, version, operating system, and device type through pattern matching. It's a free, lightweight alternative to WhatIsMyUserAgent.com for a quick browser detail check.
Key Features
The device-user-agent parser also reports screen resolution, viewport size, and pixel ratio alongside the core browser and OS detection, giving a fuller technical snapshot useful for responsive design testing. As an OS detection tool, it displays results instantly on page load with no button click required, plus a raw copyable string for pasting into a bug report. The full technical breakdown loads instantly with no button click required, so results are visible the moment the page opens. The rendering engine (Blink, Gecko, or WebKit) is now identified alongside browser and OS, and separate Copy Details, Copy Raw UA, and Copy All buttons make it easy to grab exactly the information a bug report or support ticket needs.
Common Use Cases
Web developers copy their exact user agent string to include in a cross-browser bug report. QA testers verify which browser and OS combination they're currently testing on before filing a compatibility issue. Support teams ask a customer to share this page's output to diagnose a browser-specific problem, and developers testing responsive design check their current viewport and pixel ratio values. Accessibility testers confirm the exact device pixel ratio and viewport dimensions before validating a responsive layout.
Tips for Best Results
Remember that browser extensions like privacy tools or ad blockers sometimes modify the reported user agent string, so what you see here may differ slightly from a completely unmodified browser. If you need to test how a site behaves under a different user agent, browser developer tools typically offer a way to simulate other user agent strings.
Privacy & Security
Because ToolNest processes everything entirely within your browser using client-side JavaScript, your files never leave your device. There is no server-side storage, no third-party analytics attached to your data, and no risk of a breach exposing files you processed months ago.
What is a User-Agent string and why do websites use it?
A User-Agent string identifies your browser, operating system, and device to websites, which they may use to serve appropriately formatted content.
How can developers inspect client browser details automatically?
Simply open this tool and the current browser, OS, device type, and screen details are detected and displayed automatically.
Can browser extensions change my reported user agent string?
Yes, some privacy extensions or ad blockers can modify or mask the reported user agent, so results may vary based on installed extensions.
Does this tool work the same way on mobile as desktop?
Yes, the detection logic works identically across mobile and desktop browsers, correctly identifying device type in both cases.