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User Agent Parser

Parse any user agent string into browser, operating system, device type and engine details. Shows your current UA automatically. Free, browser-based.

💻 Developer Tools Free Browser-based
Tool

What is a User Agent String?

Every browser sends a User-Agent HTTP header with each request, identifying the browser name and version, rendering engine, operating system and device type. Web servers and analytics tools use this string to tailor responses, track browser usage and diagnose compatibility issues.

Common User Agent Examples

BrowserUA Prefix
Chrome (Windows)Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36…
Safari (macOS)Mozilla/5.0 (Macintosh; Intel Mac OS X…) AppleWebKit/605…
FirefoxMozilla/5.0 (Windows NT 10.0; Win64; x64; rv:…) Gecko/…
Chrome (Android)Mozilla/5.0 (Linux; Android 14; Pixel 8) AppleWebKit…
GooglebotMozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)

Why User Agent Strings Are Unreliable

UA strings are self-reported and not validated. Any browser or script can send any UA it wants. Common reliability problems include:

  • Browser masquerading — Microsoft Edge sends a Chrome UA token (Edg/) to ensure compatibility with Chrome-targeted sites. Detecting "Chrome" without also checking for "Edg/" will mis-identify Edge as Chrome.
  • Bot spoofing — Some crawlers and scrapers set a desktop browser UA to bypass bot-blocking rules. Bot detection based solely on UA is easily circumvented.
  • User overrides — Desktop browsers let users set a custom UA string from DevTools or extensions. A mobile UA on a desktop means nothing if the user changed it manually.

Use UA detection for progressive enhancement and analytics — not for security or access control decisions.

'This is a legacy compatibility token dating back to the Netscape era. Browsers kept it to avoid being blocked by servers that checked for the "Mozilla" prefix. It has no meaning today.'], ['q' => 'Is my data uploaded to a server?', 'a' => 'No. Everything runs locally in your browser using JavaScript. Your data never leaves your device.'], ['q' => 'Why is the UA detection sometimes wrong?', 'a' => 'User agent strings do not follow a strict standard. Browsers may mimic each other (e.g. Edge reports as Chrome via the Edg/ token), and bots may spoof UA strings to avoid detection.'], ['q' => 'Where can I find a request\'s user agent string?', 'a' => 'Open browser DevTools → Network tab → select any request → look for the User-Agent request header. Server-side, it is available as the HTTP_USER_AGENT environment variable in PHP/Apache, or req.headers["user-agent"] in Node.js.'], ['q' => 'What is the difference between Chrome and Chromium in the UA?', 'a' => 'Chromium is the open-source base; Chrome adds Google-specific features. Their UA strings look nearly identical — both contain "Chrome/X.X" — but Chrome includes Google services while Chromium does not. Edge (Blink) also reports Chrome in its UA alongside the Edg/ token.'], ['q' => 'How can I change or spoof my user agent?', 'a' => 'In Chrome DevTools, open the Network conditions drawer (⋮ → More tools → Network conditions) and uncheck "Use browser default" under User agent. In Firefox, set general.useragent.override in about:config. This is useful for testing mobile layouts without a physical device.'], ]" />