User Agent Parser
Parse and decode browser user agent strings.
Frequently Asked Questions
What is a user agent string?
A user agent string is a text identifier that browsers and HTTP clients send with every request. It contains information about the browser name and version, rendering engine, operating system, device type, and platform. Servers use this to serve compatible content, detect bots, and analyze traffic.
What information does the parser extract?
The parser identifies: browser name and version (Chrome 120, Firefox 121, Safari 17), rendering engine (Blink, Gecko, WebKit), operating system and version (Windows 11, macOS 14, Android 14, iOS 17), device type (desktop, mobile, tablet), and whether the agent is a bot or crawler.
Why are user agent strings so long and confusing?
User agent strings grew organically over decades. Early browsers added other browsers' tokens to ensure compatibility — Chrome includes "Mozilla", "AppleWebKit", and "Safari" tokens despite being none of those. This legacy means parsing requires specialized knowledge of the historical format evolution.
Can I detect my own browser's user agent?
Yes — the tool auto-detects and displays your current browser's user agent string when you first load the page. You can then paste any other user agent string to analyze it. This is useful for testing browser detection logic during web development.
How accurate is bot detection?
The parser maintains a database of known bot user agents including Googlebot, Bingbot, Slurp, DuckDuckBot, and many others. It also detects generic patterns common to automated tools. However, sophisticated bots can spoof legitimate user agents, so server-side bot detection should use additional signals.