Parse user-agent strings to identify the browser, operating system, rendering engine, and device type. Detect whether a request comes from a real browser or an automated bot.
The tool automatically detects and displays your current browser's user-agent string on page load. Click 'Use My Browser' to refresh it. To analyze a different user-agent, paste it into the input field. The parser identifies: browser name and version (Chrome, Firefox, Safari, Edge, etc.), rendering engine (Blink, Gecko, WebKit), operating system and version (Windows, macOS, Linux, iOS, Android), device type (Desktop, Mobile, Tablet), and whether the user-agent belongs to a known bot or crawler (Googlebot, Bingbot, etc.). Use the preset buttons to quickly test common user-agent strings for different browsers, mobile devices, and search engine bots.
User-agent parsing is crucial for web developers implementing browser-specific features or workarounds, analytics platforms classifying traffic by browser, OS, and device, security systems detecting suspicious or spoofed user-agents, SEO professionals verifying how search engine bots crawl their sites, A/B testing platforms targeting specific browser segments, content delivery networks (CDNs) serving optimized assets based on device type, customer support teams reproducing bugs reported by users on specific browsers, and quality assurance testing where testers need to verify behavior across different user-agent strings without switching browsers.
User-agent strings follow a loosely defined format originating from the HTTP specification (RFC 9110). A typical Chrome UA string contains: Mozilla/5.0 (compatibility token), platform info (Windows NT 10.0; Win64; x64), AppleWebKit/537.36 (engine version), Chrome/120.0.0.0 (browser version), and Safari/537.36 (legacy compatibility). Parsing uses regular expressions to match known patterns - Chrome is detected via /Chrome\/(\d+)/, Firefox via /Firefox\/(\d+)/, Safari via /Version\/(\d+).*Safari/. Bot detection matches against known crawler signatures like 'Googlebot', 'bingbot', 'Baiduspider'. Modern alternatives to user-agent strings include Client Hints (Sec-CH-UA headers) which provide structured browser information without the complexity of parsing UA strings.
A user-agent string is a text identifier sent by browsers and HTTP clients with every request, telling the server what software is making the request. It typically includes the browser name and version, rendering engine, operating system, and device information. For example: 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 Chrome/120.0.0.0 Safari/537.36'.
Yes, user-agent strings can be easily changed or 'spoofed' by browser extensions, developer tools, or programmatic HTTP clients. This is why user-agent detection should not be used for security purposes. It's commonly used for analytics, content optimization, and compatibility workarounds, but never as an authentication or authorization mechanism.
Client Hints (Sec-CH-UA) are a modern replacement for user-agent strings proposed by Google. Instead of one complex string, structured headers provide specific information: Sec-CH-UA for browser brand, Sec-CH-UA-Mobile for mobile detection, and Sec-CH-UA-Platform for OS. They're opt-in, privacy-respecting, and easier to parse than traditional UA strings.
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