Why do browsers still send long User-Agent strings?

Legacy tokens like Mozilla/5.0 exist for backward compatibility with servers that check for specific substrings. Modern browsers also add freeze/reduction strategies to shrink what they reveal.

Can the parser detect bots?

It matches known bot user-agents (Googlebot, Bingbot, curl, wget, etc.). It can be fooled by a spoofed UA — treat bot detection as a hint, not a security boundary.

Does this work offline?

Yes. Parsing is pure JavaScript with no network calls. Once the page loads you can disconnect and keep using it.

User Agent Parser

User Agent String

Your browser's user agent will be auto-filled on load.

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Paste any user agent string to identify the browser, rendering engine, operating system, device type, and bot detection.