liminfo

User Agent Parser

Free web tool: User Agent Parser

Your current browser User Agent is displayed automatically.

About User Agent Parser

The User Agent Parser is a free, browser-based tool that decodes User Agent strings into human-readable information about the browser, rendering engine, operating system, and device type. When you open the page, it automatically reads `navigator.userAgent` and displays a parsed breakdown of your current browser environment. You can also paste any UA string manually to analyze it — useful for debugging browser compatibility issues, testing server-side UA detection logic, or investigating analytics data.

The parser identifies the following browsers by name and version: Chrome, Firefox, Safari, Microsoft Edge, Opera (OPR), Samsung Browser, Naver Whale, and Internet Explorer. It correctly handles the UA spoofing that modern browsers do — for example, Edge includes "Chrome" in its UA string, so the parser checks for "Edg/" first before falling back to Chrome detection. For rendering engines, it identifies Blink (Chrome-based), WebKit (Safari), Gecko (Firefox), and Trident (Internet Explorer).

OS detection covers Windows (NT 10.0/6.3/6.2/6.1 → 10/11, 8.1, 8, 7), macOS (version from Mac OS X token), Chrome OS, Android (version number), iOS (iPhone/iPad, version from CPU OS token), and Linux (with Ubuntu, Fedora, and Debian variant detection). Device classification distinguishes Mobile (iPhone, iPod, Android Mobile), Tablet (iPad, Android non-mobile), Bot/Crawler (Googlebot, Bingbot, Spider, Slurp, Whale), and Desktop.

Key Features

  • Auto-detects your current browser's User Agent string on page load using `navigator.userAgent`
  • Identifies 8 browsers: Chrome, Firefox, Safari, Edge, Opera, Samsung Browser, Naver Whale, Internet Explorer
  • Detects 4 rendering engines: Blink (Chrome-based), WebKit (Safari), Gecko (Firefox), Trident (IE)
  • OS detection for Windows (7/8/8.1/10/11), macOS, Chrome OS, Android, iOS, and Linux variants
  • Device type classification: Mobile, Tablet, Desktop, and Bot/Crawler detection
  • Correctly resolves UA spoofing (Edge includes "Chrome" token; Samsung Browser includes "Chrome" token)
  • Manual input mode: paste any UA string and click Analyze to parse it independently
  • Reset button to restore your current browser's UA after testing custom strings

Frequently Asked Questions

What is a User Agent string?

A User Agent (UA) string is a text header that browsers send with every HTTP request to identify themselves to web servers. It typically contains the browser name and version, rendering engine, operating system, and sometimes device information. Servers use this information for analytics, conditional content delivery, and compatibility workarounds.

Why does Chrome's User Agent string mention "Mozilla" and "Safari"?

This is a historical artifact. Early browsers sent "Mozilla/1.0" in their UA. When Netscape added new features, other browsers included "Mozilla" to receive the same content. Chrome later built on WebKit (Safari's engine) and included "Safari" for compatibility. Modern UA strings are a layered accumulation of compatibility tokens, not an accurate description of the browser.

How does the parser tell Edge apart from Chrome?

Both Edge and Chrome include "Chrome/XX.X" in their UA strings. The parser checks for "Edg/" (the Edge-specific token) before checking for "Chrome", so Edge is correctly identified even though its UA contains the Chrome token. This ordering matters — if Chrome were checked first, Edge would be misidentified.

Can this detect bot traffic?

Yes. The parser checks for common bot signatures including "Bot", "Crawler", "Spider", "Slurp" (Yahoo), "Googlebot", and "Bingbot". When any of these tokens are found, the device type is set to "Bot/Crawler". However, sophisticated bots can spoof any UA string, so client-side UA parsing is not a reliable bot-detection mechanism for security purposes.

How do I know if a UA string is from a mobile device?

The parser checks for "Mobile", "Android.*Mobile", "iPhone", and "iPod" tokens. If any match, the device is classified as Mobile and the `mobile` flag is set to true. Tablet detection looks for "iPad", "Android" without "Mobile", or "Tablet". The mobile flag is displayed as a green badge next to the device type in the results.

What is the difference between the rendering engine and the browser?

The rendering engine is the core software that parses HTML/CSS and paints pixels. Multiple browsers can share the same engine: Chrome, Edge, Opera, Samsung Browser, and Brave all use Blink (a fork of WebKit). Safari uses WebKit. Firefox uses Gecko. Internet Explorer used Trident. Identifying the engine is important for determining which CSS features and JavaScript APIs are available.

Does it detect Windows 11?

Windows 11 reports the same `Windows NT 10.0` token as Windows 10 in its User Agent string. Microsoft deliberately chose not to change the NT version to avoid breaking UA-based detection logic. The parser displays "Windows 10/11" for this token to reflect the ambiguity accurately.

Can I use this tool to test what User Agent a headless browser sends?

Yes. Run your headless browser (Puppeteer, Playwright, etc.), capture the UA string from `navigator.userAgent`, paste it into this tool, and click Analyze. This is useful for verifying that your automation tools send a realistic UA string and for debugging server-side UA-based access control.