User Agent Parsing: Detect Browsers and Devices Online - Free

User-Agent strings are sent by browsers with every HTTP request. Parsing them helps identify the browser, operating system, and device type - useful for analytics, troubleshooting, and optimization.

What is a User-Agent?

A User-Agent string identifies the client software making an HTTP request:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

This tells us:

Browser: Chrome 120
OS: Windows 10/11
Device: Desktop
Engine: Blink

Why Parse User-Agents?

1. Analytics

Understand your users’ browsers and devices for better optimization.

2. Troubleshooting

Debug browser-specific issues reported by users.

3. Content Optimization

Serve different content for mobile vs desktop.

4. Security

Detect bots, scrapers, and suspicious clients.

Using Our User Agent Parser

Our User Agent Parser provides instant parsing:

Paste a User-Agent string in the input
Click “Parse” or press Enter
View results including browser, OS, and device
Try sample UAs to explore different formats

Parse Your Own UA

Click “My UA” to parse your current browser’s User-Agent.

Common User-Agent Patterns

Chrome on Windows

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Safari on macOS

Mozilla/5.0 (Macintosh; Intel Mac OS X 14_2) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2 Safari/605.1.15

Firefox on Linux

Mozilla/5.0 (X11; Linux x86_64; rv:121.0) Gecko/20100101 Firefox/121.0

iPhone Safari

Mozilla/5.0 (iPhone; CPU iPhone OS 17_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2 Mobile/15E148 Safari/604.1

Googlebot

Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)

Browser Detection

Major Browsers

Browser	Identifier
Chrome	`Chrome/`
Firefox	`Firefox/`
Safari	`Safari/` (without Chrome)
Edge	`Edg/`
Opera	`OPR/` or `Opera/`
IE	`MSIE` or `Trident/`

Detection Order

Always check in the right order to avoid false positives:

if (ua.includes('Edg/')) browser = 'Edge';
else if (ua.includes('OPR/')) browser = 'Opera';
else if (ua.includes('Chrome/')) browser = 'Chrome';
else if (ua.includes('Firefox/')) browser = 'Firefox';
else if (ua.includes('Safari/')) browser = 'Safari';

Operating System Detection

Common Patterns

if (ua.includes('Windows NT 10')) os = 'Windows 10/11';
else if (ua.includes('Mac OS X')) os = 'macOS';
else if (ua.includes('Android')) os = 'Android';
else if (ua.includes('iPhone') || ua.includes('iPad')) os = 'iOS';
else if (ua.includes('Linux')) os = 'Linux';

Device Type Detection

function getDeviceType(ua) {
  if (/Mobi|Android|iPhone/i.test(ua)) return 'Mobile';
  if (/Tablet|iPad/i.test(ua)) return 'Tablet';
  if (/bot|crawler|spider/i.test(ua)) return 'Bot';
  return 'Desktop';
}

Code Examples

JavaScript

function parseUserAgent(ua) {
  const result = {
    browser: { name: '', version: '' },
    os: { name: '', version: '' },
    device: { type: 'Desktop' }
  };

  // Browser detection
  if (ua.includes('Edg/')) {
    result.browser.name = 'Edge';
    result.browser.version = ua.match(/Edg\/(\d+)/)?.[1];
  } else if (ua.includes('Chrome/')) {
    result.browser.name = 'Chrome';
    result.browser.version = ua.match(/Chrome\/(\d+)/)?.[1];
  } else if (ua.includes('Firefox/')) {
    result.browser.name = 'Firefox';
    result.browser.version = ua.match(/Firefox\/(\d+)/)?.[1];
  }

  // OS detection
  if (ua.includes('Windows')) {
    result.os.name = 'Windows';
  } else if (ua.includes('Mac OS X')) {
    result.os.name = 'macOS';
  } else if (ua.includes('Android')) {
    result.os.name = 'Android';
    result.device.type = 'Mobile';
  } else if (ua.includes('iPhone')) {
    result.os.name = 'iOS';
    result.device.type = 'Mobile';
  }

  return result;
}

Python

import re

def parse_user_agent(ua):
    result = {
        'browser': {'name': '', 'version': ''},
        'os': {'name': '', 'version': ''},
        'device': {'type': 'Desktop'}
    }

    # Browser detection
    if 'Edg/' in ua:
        result['browser']['name'] = 'Edge'
        match = re.search(r'Edg/(\d+)', ua)
        result['browser']['version'] = match.group(1) if match else ''
    elif 'Chrome/' in ua:
        result['browser']['name'] = 'Chrome'
        match = re.search(r'Chrome/(\d+)', ua)
        result['browser']['version'] = match.group(1) if match else ''

    # Device type
    if any(x in ua.lower() for x in ['mobile', 'android', 'iphone']):
        result['device']['type'] = 'Mobile'

    return result

Best Practices

1. Use Feature Detection

Instead of browser detection, detect features:

// Avoid
if (browser === 'Safari') {
  // Safari-specific code
}

// Better
if ('webkitURL' in window) {
  // Feature-specific code
}

2. Don’t Rely on Exact Versions

User-Agent strings can be spoofed or modified.

3. Consider Privacy

GDPR and other regulations may apply to UA data collection.

4. Keep Updated

Browser versions and UA formats change frequently.

Bot Detection

Common bot patterns:

const botPatterns = [
  'googlebot', 'bingbot', 'slurp', 'duckduckbot',
  'baiduspider', 'yandexbot', 'sogou', 'exabot',
  'facebot', 'facebookexternalhit', 'twitterbot',
  'linkedinbot', 'pinterest', 'crawler', 'spider', 'bot'
];

function isBot(ua) {
  const lowerUA = ua.toLowerCase();
  return botPatterns.some(pattern => lowerUA.includes(pattern));
}

Conclusion

User-Agent parsing provides valuable insights about your users’ browsers and devices. Use our User Agent Parser for quick, accurate parsing.

Remember: User-Agent strings can be spoofed, so use this information carefully and consider feature detection when possible.