User Agent Parser
Parse any user agent string to identify browser, OS, and device.
Paste a user agent string or use the button below to detect yours.
What Is a User Agent String?
A user agent (UA) string is a text identifier that web browsers and HTTP clients send with every request. It tells the server which browser, operating system, device, and rendering engine the visitor is using. Originally defined in RFC 7231, user agent strings have grown increasingly complex over the decades as browsers adopted compatibility tokens to avoid being blocked by UA-sniffing websites.
Why Parse User Agents?
Developers, QA engineers, and analytics teams parse user agent strings for several reasons: identifying browser-specific bugs, segmenting traffic by device type (desktop, mobile, tablet, bot), detecting web crawlers, and building responsive experiences based on client capabilities. Understanding a visitor's browser and OS version helps reproduce issues and deliver optimized content.
Anatomy of a User Agent String
A typical user agent contains several components: the product token (e.g., Mozilla/5.0), the platform and OS identifier (e.g., Windows NT 10.0; Win64; x64), the rendering engine (e.g., AppleWebKit/537.36 or Gecko/20100101), and the browser name and version (e.g., Chrome/120.0.0.0). Some strings also include bot identifiers like Googlebot or bingbot.
Client Hints and the Future
Modern browsers are moving toward User-Agent Client Hints (UA-CH), a newer standard that provides structured, low-entropy data instead of the bloated legacy string. However, the traditional UA string remains universally supported and is still the primary method for identifying clients. This parser handles both modern and legacy user agent formats, running entirely in your browser with no data sent to any server.