Instantly detect, analyze, and parse your browser user agent string with comprehensive details about browser type, version, rendering engine, operating system, device information, and user agent components. Free user agent analyzer providing detailed UA string breakdown for developers, testers, and technical troubleshooting.
A "What Is My User Agent" tool is a specialized web utility that detects, displays, and analyzes your browser's user agent (UA) string—the identification text that your browser automatically sends to every website you visit. This tool captures the raw user agent string from your browser's HTTP headers and parses it to extract meaningful information including browser brand and version number, browser rendering engine (Blink, Gecko, WebKit) and engine version, operating system family (Windows, macOS, Linux, Android, iOS), OS version and architecture details (64-bit, ARM, etc.), device type and manufacturer (iPhone, Samsung Galaxy, etc.), system capabilities and compatibility information, and individual user agent components and tokens. User agent strings serve as the browser's "digital passport," providing websites with essential information about your browsing environment so they can deliver appropriately formatted content and compatible features. When you visit a website, your browser includes the user agent string in the HTTP request header. The server reads this string to determine whether to serve a mobile-optimized layout or desktop version, which video codec formats are supported, whether modern CSS and JavaScript features are available, and how to optimize images and resources for your device. While this mechanism helps websites provide better user experiences, user agent strings have evolved into complex, sometimes confusing text strings with historical baggage and inconsistent formats across different browsers. Understanding your user agent string is valuable for multiple scenarios. Web developers and quality assurance testers use user agent analysis to verify how websites detect and respond to different browsers, test responsive design behavior across device types, debug browser-specific rendering issues, and ensure proper content delivery to various platforms. Technical support teams request user agent information when troubleshooting website compatibility problems, as it provides immediate insight into the user's browsing environment without requiring users to manually identify their browser, operating system, and version details. Privacy-conscious users examine their user agent strings to understand what identifying information their browser shares with websites and how it might contribute to browser fingerprinting and tracking. Our What Is My User Agent tool provides instant, comprehensive analysis of your browser's user agent string with detailed component breakdown, human-readable interpretation of encoded information, browser and engine identification, operating system and device parsing, user agent token analysis, and comparison with standard user agent formats. The tool displays both your raw user agent string (exactly as sent to servers) and parsed components with clear explanations, helping you understand what information your browser shares with websites. Whether troubleshooting browser compatibility issues, testing web applications across different user agents, analyzing privacy implications of user agent fingerprinting, or simply curious about your browser's identification string, this tool provides complete user agent analysis in a clear, accessible format with detailed technical insights.
Visit the What Is My User Agent tool page in your web browser.
The tool automatically detects and displays your user agent string immediately.
Review the raw user agent string: complete text as sent to websites.
Check browser identification: brand name (Chrome, Firefox, Safari, Edge, etc.).
Verify browser version: major, minor, and build numbers extracted from UA.
Examine rendering engine: Blink, Gecko, or WebKit with version number.
Analyze operating system: platform (Windows, macOS, Android, iOS, Linux).
Check OS version: specific version number and architecture (64-bit, ARM).
Review device information: device type (mobile, tablet, desktop) and model.
Examine user agent components: individual tokens and their meanings.
Understand compatibility indicators: what features/standards are supported.
Copy user agent string for technical support tickets or bug reports.
Use parsed information to understand what data your browser shares.
Compare with other browsers/devices to see UA string variations.
Test with modified user agents using browser extensions to see differences.
Instantly view your complete user agent string
Parse and analyze UA components in detail
Identify exact browser name and version
Detect operating system and device details
Understand rendering engine information
Essential for technical support and troubleshooting
Verify browser detection on websites
Test user agent changes and modifications
Analyze privacy implications of UA sharing
Useful for web developers and testers
Completely free with no registration
No installation or downloads required
| Browser | Example User Agent String | Key Components |
|---|---|---|
| Chrome (Windows) | Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36 | Windows 10 64-bit, Blink engine, Chrome 120 |
| Firefox (macOS) | Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:121.0) Gecko/20100101 Firefox/121.0 | macOS 10.15, Gecko engine, Firefox 121 |
| Safari (iOS) | 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 | iPhone iOS 17.2, WebKit, Safari 17.2 |
| Edge (Windows) | Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36 Edg/120.0.0.0 | Windows 10, Blink engine, Edge 120 |
| Android Chrome | Mozilla/5.0 (Linux; Android 14; Pixel 7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Mobile Safari/537.36 | Android 14, Pixel 7, Chrome Mobile 120 |
User agent strings follow a semi-standardized format with multiple components separated by spaces and parentheses. The general structure is: Mozilla/5.0 (Platform; OS Details) Engine/Version Browser/Version. Breaking down a typical Chrome UA: 'Mozilla/5.0' - historical identifier (all modern browsers include this for compatibility), '(Windows NT 10.0; Win64; x64)' - platform information (operating system, architecture), 'AppleWebKit/537.36 (KHTML, like Gecko)' - rendering engine (WebKit origin, standards compatibility), 'Chrome/120.0.0.0' - browser name and version, 'Safari/537.36' - additional compatibility indicator. The presence of multiple browser names (Chrome includes Safari, Edge includes Chrome and Safari) stems from historical web compatibility issues where websites checked for specific browser names. Including multiple identifiers ensures compatibility with legacy detection code.
The browser and rendering engine components reveal critical information about your browsing software. Browser identifiers: 'Chrome/120.0.0.0' indicates Google Chrome version 120 major release, 'Firefox/121.0' shows Mozilla Firefox version 121, 'Safari/17.2' for Apple Safari, 'Edg/120.0.0.0' for Microsoft Edge (note: 'Edg' not 'Edge'). Rendering engines: 'AppleWebKit/537.36' - WebKit engine used by Safari and Chromium-based browsers, 'Gecko/20100101' - Firefox's rendering engine, 'Blink' - Chrome's engine (forked from WebKit, implicit in Chrome user agents). Understanding engines matters because: browsers using same engine (Chrome, Edge, Opera) render pages identically, engine versions indicate feature support, and developers may need to work around engine-specific bugs. Version numbers help determine: whether browser is up-to-date for security, which web APIs and features are supported, and compatibility with modern CSS and JavaScript.
Platform components in user agents reveal operating system details. Common patterns: Windows: 'Windows NT 10.0' (Windows 10/11), 'Win64; x64' (64-bit architecture), 'WOW64' (32-bit browser on 64-bit Windows). macOS: 'Macintosh; Intel Mac OS X 10_15_7' (macOS Catalina 10.15.7), 'Mac OS X 10_15' (version with underscores, not dots). Linux: 'X11; Linux x86_64' (Linux with X Window System, 64-bit), 'Ubuntu' may appear for specific distributions. Android: 'Linux; Android 14' (Android version), device model may appear ('Pixel 7', 'SM-G991B'). iOS/iPadOS: 'iPhone; CPU iPhone OS 17_2 like Mac OS X' (iPhone iOS 17.2), 'iPad; CPU OS 17_2' (iPad). Chrome OS: 'CrOS x86_64' (Chromebook). OS information helps websites: deliver platform-appropriate resources, determine available system fonts, optimize for touch vs mouse input, and identify mobile vs desktop contexts. However, privacy initiatives are reducing OS detail granularity to prevent fingerprinting.
Device information in user agents helps identify hardware and form factors. Device indicators: Mobile devices: presence of 'Mobile' keyword, specific device models ('iPhone', 'iPad', 'Pixel 7', 'SM-G991B' for Samsung), screen size sometimes implied. Tablets: 'iPad' explicitly identified, Android tablets may show 'Tablet' or omit 'Mobile'. Desktop: absence of mobile indicators, 'Macintosh', 'Windows', 'X11' suggest desktop. Smart TVs and consoles: 'SmartTV', 'PlayStation', 'Xbox', 'Nintendo'. Bots and crawlers: 'Googlebot', 'Bingbot', typically identify themselves. Device detection helps: responsive design decisions (mobile vs tablet vs desktop layout), touch interface optimization, image resolution and size optimization, and feature availability (camera access on mobile, file system on desktop). However, device detection via user agent is imprecise—use CSS media queries and JavaScript feature detection for reliable responsive behavior rather than relying solely on user agent parsing.
User agent strings contribute to browser fingerprinting and tracking concerns. Privacy risks: Combined with other data (screen resolution, fonts, Canvas fingerprint), user agents help create unique identifiers, enable cross-site tracking without cookies, persist even when clearing cookies/cache, and can reveal system details useful for targeted attacks. Privacy reduction initiatives: Chrome User-Agent Reduction: gradually freezing UA versions to generic values (Chrome 110+ reduced to major version only), unified Windows version reporting, reduced granularity. Client Hints: newer mechanism requiring explicit server requests, structured format with permission model, separates low-entropy (public) from high-entropy (gated) data. Privacy-focused browsers: Brave randomizes or limits UA information, Firefox includes Enhanced Tracking Protection (reduces fingerprinting), Tor Browser standardizes UA across users (same UA for everyone). Best practices: don't rely on UA alone for critical decisions, respect Do Not Track (DNT) signals, minimize UA parsing and data retention, use feature detection over UA sniffing. For users: privacy browsers reduce UA tracking exposure, extensions can rotate user agents, VPNs don't hide UA (only IP address), Tor provides strongest UA privacy protection.
Web developers extensively use user agent analysis for testing and debugging. Common scenarios: Cross-browser testing: verify detection logic across different UAs, test responsive behavior for mobile/tablet/desktop, ensure polyfills load for legacy browsers, validate feature detection fallbacks. Debugging: reproduce user-reported issues by testing with their UA, identify browser-specific rendering bugs, verify analytics tracking correctly captures browser data. Content optimization: serve WebP/AVIF images to supporting browsers, provide appropriate video codecs (H.264, VP9, AV1), optimize JavaScript bundles for browser capabilities, deliver mobile-optimized content. Testing approaches: browser DevTools allow UA override without extensions (F12 > Network conditions), automated testing (Playwright, Selenium) can set custom UAs, real device testing more reliable than UA simulation, consider using BrowserStack or similar for real browser matrix. Best practices: use feature detection over UA sniffing, treat UA as suggestion for optimization not requirement, implement progressive enhancement (work without optimal detection), and maintain fallbacks when UA parsing fails. The future of browser identification is moving toward explicit permission (Client Hints), feature detection, and privacy-preserving methods rather than passive UA string parsing.
A: A user agent (UA) string is a text identifier that your web browser automatically sends with every HTTP request to websites. It contains encoded information about your browsing environment including: browser name and version (Mozilla/5.0, Chrome/120.0.0.0), browser rendering engine and version (AppleWebKit/537.36, Gecko/20100101), operating system and version (Windows NT 10.0, Mac OS X 10_15_7, Android 14), device information (iPhone, iPad, Samsung, Pixel), system architecture (Win64, x64, ARM), browser build details and identifiers. The format follows a semi-standardized structure: Mozilla/5.0 (Platform; OS) Engine/Version Browser/Version. For example: 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36' reveals Windows 10 64-bit, Blink rendering engine, Chrome 120. User agents help websites deliver appropriate content, but can be used for fingerprinting and tracking.
A: Websites use user agent strings for several legitimate technical purposes: Content optimization: Serve mobile-optimized layouts for smartphones/tablets, deliver desktop versions for computers, provide touch-friendly interfaces for touch devices. Browser compatibility: Detect outdated browsers and suggest upgrades, implement browser-specific code for rendering differences, serve appropriate polyfills for missing features, avoid serving unsupported content (modern CSS/JS to old browsers). Media delivery: Serve compatible video codecs (H.264, VP9, AV1), optimize image formats (WebP, AVIF for supporting browsers), adjust quality based on device capabilities. Analytics and statistics: Track browser market share and usage trends, identify which browsers visit the site, inform development priorities and browser support decisions. Security: Detect unusual patterns (bot traffic, automated requests), block known malicious user agents, implement rate limiting per client type. However, user agent sniffing has limitations and can be problematic, so modern development favors feature detection over user agent parsing when possible.
A: User agent strings have significant reliability issues and limitations: Can be easily modified: Browser extensions can change user agents with one click, developer tools allow user agent override for testing, privacy tools may randomize or mask user agents, automated bots often spoof legitimate browser user agents. Standardization problems: No strict enforcement of user agent format, different browsers report information inconsistently, historical baggage creates confusing strings (Chrome reports as Safari and Mozilla), mobile/desktop modes can change user agent. Privacy reduction initiatives: Chrome freezing user agent (reducing version granularity), client hints replacing detailed user agent information, browsers removing unique identifying information. Best practices for developers: Use feature detection instead of user agent sniffing (if ('serviceWorker' in navigator)), treat user agent as suggestion, not fact, use for analytics only, not critical functionality, implement fallbacks when user agent parsing fails, consider newer Client Hints API for server-side needs. Accuracy estimate: 85-90% accurate for general browser/OS detection, but unreliable for specific device models, versions may be frozen or generic, and assume possibility of spoofing.
A: User agent and browser fingerprinting are related but distinct identification methods: User agent string: Single piece of data sent with every HTTP request, easily readable text format, can be changed/spoofed easily, provides basic browser/OS/device information, relatively low uniqueness (many users share same UA), primarily used for compatibility and analytics. Browser fingerprinting: Combines multiple data points for unique identification including user agent string, screen resolution and color depth, installed fonts list, Canvas/WebGL fingerprints, timezone and language, installed plugins, system hardware details, audio context fingerprints. Result: highly unique identifier (often 99%+ unique), difficult to modify all components, persists even when cookies cleared, used for tracking across sessions and sites. Privacy implications: User agent alone is not sufficient for individual tracking, fingerprinting enables cross-site tracking without consent, privacy-focused browsers (Brave, Firefox, Tor) implement anti-fingerprinting, regulations (GDPR, CCPA) restrict fingerprinting practices. Legitimate uses: fraud prevention and bot detection, protecting against account takeover, securing financial transactions. Invasive uses: cross-site tracking without consent, building detailed user profiles, bypassing cookie deletion and privacy tools.
A: Yes, user agents can be changed through multiple methods: Browser extensions: User-Agent Switcher for Chrome/Firefox (easy interface to switch between presets), allows custom user agent strings, temporary per-session changes. Developer tools: All major browsers allow UA override (Chrome DevTools: F12 > Network conditions > User agent, Firefox: F12 > Responsive Design Mode > User agent), useful for testing, resets when DevTools closed. Browser settings: Some browsers allow permanent UA modification, Brave/Firefox have built-in options for stricter privacy. Command-line flags: Launch browser with custom user agent flag (--user-agent='custom string'). Reasons to change user agent: Testing: Web developers test how sites respond to different browsers, verify mobile/desktop responsive behavior, debug browser-specific issues. Accessing mobile sites: View mobile version of site on desktop, test mobile-specific features. Privacy: Reduce fingerprinting uniqueness, rotate user agents to avoid tracking. However, consider drawbacks: May break website functionality (sites optimized for detected browser), can create inconsistent experiences, may violate website terms of service, doesn't prevent other fingerprinting methods, legitimate sites may block suspicious user agents. Better alternatives for privacy: use privacy-focused browsers (Brave, Firefox with Enhanced Tracking Protection, Tor Browser), enable built-in anti-fingerprinting features, use VPN with privacy protections, block third-party cookies and trackers. Change user agent for testing/development, but avoid for deception.
A: Client Hints are a newer, privacy-conscious replacement for traditional user agent strings being adopted by modern browsers. How they work: Server explicitly requests needed information via Accept-CH header (Accept-CH: Sec-CH-UA, Sec-CH-UA-Mobile, Sec-CH-UA-Platform), browser sends only requested hints with subsequent requests, structured format (easier to parse than UA strings), split into low-entropy (public) and high-entropy (requires permission) hints. Low-entropy hints (always available): Sec-CH-UA: browser brand and significant version, Sec-CH-UA-Mobile: whether mobile device (true/false), Sec-CH-UA-Platform: operating system. High-entropy hints (require permission): Sec-CH-UA-Platform-Version: detailed OS version, Sec-CH-UA-Arch: CPU architecture (x86, ARM), Sec-CH-UA-Model: device model, Sec-CH-UA-Full-Version-List: complete browser version details. Benefits over user agent strings: Privacy-preserving: servers only get information they explicitly request, reduces passive fingerprinting surface, user consent for detailed information, browser can refuse high-entropy hints. Structured data: JSON format easier to parse, no regex required, consistent across browsers, extensible for future needs. Active negotiation: servers declare what they need, browsers control what they share, reduces unnecessary data transmission. Current status: Chromium-based browsers (Chrome, Edge, Opera) support since 2021, Firefox and Safari evaluating/implementing, user agent string being gradually frozen in Chrome. Migration strategy: servers should request Client Hints explicitly, maintain user agent fallback for older browsers, use feature detection when possible, prepare for reduced user agent granularity. Client Hints represent the future of browser identification, balancing website needs with user privacy.