User-Agent Parsing: Knowing Your Visitors

Every time a browser requests a web page, it sends a User-Agent (UA) string in the HTTP headers. This string contains information about the user's browser, version, operating system, and device type.

Why Parse the User-Agent?

While responsive design (CSS media queries) is the best way to handle layout changes, backend UA parsing is useful for analytics, directing users to specific app store links, or delivering optimized payloads to specific legacy browsers.

The Messy Reality

UA strings are notoriously messy due to historical browser spoofing (e.g., almost every browser claims to be "Mozilla"). To understand exactly what your browser is sending, check out our User-Agent Parser tool.