User Agent Analyzer
Parse and analyze browser user agent strings with detailed information extraction. Identify browsers, operating systems, devices, and more from HTTP user agent headers.
Example User Agents
What is a User Agent?
A user agent is a computer program that acts as an intermediary between you and the internet. When your browser connects to a website, it sends a user agent string - a unique identifier that contains detailed technical information about your device, browser, and operating system.
This string of text serves as an "ID card" for your browser, helping websites deliver the most appropriate content and functionality for your specific setup. Every HTTP request includes this User-Agent header, enabling seamless communication between browsers and web servers.
Browser Identification
User agents help websites identify your browser type and version, ensuring compatibility and optimal rendering. This prevents broken layouts and missing features on websites.
Modern websites use this information to serve browser-specific CSS, JavaScript, and functionality, creating a seamless browsing experience.
Device Detection
User agent strings reveal whether you're using a mobile device, tablet, or desktop computer. This enables responsive design and mobile-optimized experiences.
Websites automatically serve mobile versions with touch-friendly interfaces and optimized layouts based on your device type.
Understanding User Agent Components
Browser Name
Chrome, Firefox, Safari, Edge
Version Number
120.0.0.0, 117.0, 16.6
Operating System
Windows, macOS, Linux, Android, iOS
Engine Details
WebKit, Gecko, Blink
Why User Agent Detection Matters
Web Development & Testing
Developers use user agent analysis to test websites across different browsers and devices, ensuring consistent functionality and appearance.
Analytics & Statistics
Website owners analyze user agent data to understand their audience's browser preferences and device usage patterns for better optimization.
Security & Bot Detection
User agent strings help identify legitimate browsers versus bots, crawlers, and potentially malicious automated traffic for enhanced security.
Content Optimization
Websites use user agent information to serve mobile-optimized layouts, touch-friendly interfaces, and device-appropriate media formats.
Feature Detection
When modern feature detection APIs aren't available, user agent parsing provides fallback methods for determining browser capabilities.
Localization
User agents often include language preferences, helping websites automatically serve content in the user's preferred language.
Common User Agent Examples
C Chrome on Windows
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36F Firefox on Linux
Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/117.0S Safari on iPhone
Mozilla/5.0 (iPhone; CPU iPhone OS 17_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Mobile/15E148 Safari/604.1Frequently Asked Questions
Can I change my user agent?
Yes, you can modify your user agent string through browser developer tools, extensions, or specialized software. This process is called "user agent spoofing" and is commonly used for testing website compatibility across different browsers and devices.
Is my user agent unique?
While user agent strings aren't completely unique, they can be combined with other browser fingerprinting techniques to create a relatively unique identifier. Popular browsers on common operating systems will share similar user agent strings.
Why do user agents mention multiple browsers?
Modern user agent strings contain legacy compatibility tokens. For example, Chrome's user agent includes "Safari" and "Mozilla" for historical compatibility reasons, ensuring websites built for older browsers continue to work.
Do search engine bots have user agents?
Yes, search engine crawlers like Googlebot, Bingbot, and others identify themselves through specific user agent strings. This helps websites provide appropriate content and follow robots.txt directives.
Related Tools & Resources
Professional User Agent Analysis Tool
Our free online user agent parser provides comprehensive browser and device detection with detailed technical analysis. Perfect for web developers, SEO professionals, and system administrators who need accurate user agent string interpretation.
Key Features:
- Instant browser identification and version detection
- Operating system and architecture analysis
- Mobile, tablet, and desktop device classification
- Bot and crawler detection capabilities
- Rendering engine identification
Use Cases:
- Cross-browser compatibility testing
- Website analytics and visitor insights
- Mobile responsiveness verification
- Security analysis and bot identification
- Technical support and troubleshooting
Technical Implementation
HTTP Header Structure
GET /page HTTP/1.1
Host: example.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36
Accept: text/html,application/xhtml+xml
Accept-Language: en-US,en;q=0.9The User-Agent header is automatically included in every HTTP request your browser makes, providing essential information for content negotiation and compatibility.
JavaScript Access
const userAgent = navigator.userAgent;
console.log(userAgent);
const isChrome = userAgent.includes('Chrome');
const isMobile = /Mobile|Android/.test(userAgent);Client-side JavaScript can access the user agent string through the navigator.userAgent property for dynamic feature detection and responsive behavior.