🌐 Dev

User-Agent Parser

Parse User-Agent strings and identify browser, version, operating system and device type. Perfect for debugging access logs.

User-Agent

Cole uma string User-Agent acima para ver a análise

Exemplos para testar

What that Mozilla/5.0 string actually means

You are staring at an nginx access log, or chasing a bug that only happens on one customer's phone, and what you have is a long line starting with Mozilla/5.0. Paste the string here (or click the button to use your own) and it turns into four cards: browser and version, operating system, device type and rendering engine, plus tags flagging mobile devices, bots and programmatic access from curl, wget and friends.

User-Agents lie for historical reasons: every browser announces itself as Mozilla/5.0, Chrome carries Safari in its string and Edge carries Chrome. The parser (the ua-parser-js library) untangles this by token order and combination, not by naive substring search. Two version gotchas: Windows 11 still identifies itself as Windows NT 10.0, and macOS froze at 10_15_7, so the version you see can be older than the real one.

For log analysis, treat the tags as hints, not proof: bot detection is keyword-based (bot, crawler, spider), so a scraper masquerading as Chrome sails right through. A User-Agent is a claim made by the client, not an identity. Parsing happens in your browser and the string is never sent to a server (the library loads from a CDN). The built-in samples are handy for comparing desktop, iPhone and Googlebot formats.

Frequently asked questions

Why does it say Windows 10 when I run Windows 11?

Because Windows 11 sends Windows NT 10.0 in the User-Agent, same as Windows 10. The string alone cannot tell them apart; that information now only comes through Client Hints.

Can I rely on the User-Agent to block bots?

No. The string is self-declared and any script can imitate a legitimate Chrome. Use it for stats and debugging, not as a security mechanism.

Why do some fields come back as unknown?

The string simply does not carry that data, or carries it in a shape the library does not recognize. Bots like Googlebot, for instance, report neither an operating system nor an engine.

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