KitJade
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User-Agent Parser

Decode browser, OS and bot details from a UA string.

Use the User-Agent Parser tool

Runs in your browserUpdated Report a problem

What this user-agent parser does

User-Agent Parser breaks a User-Agent string into browser name and version, rendering engine, operating system, device type and a bot flag. It recognises common search crawlers, AI crawlers and command-line clients alongside mainstream browsers.

User-Agent strings are self-reported and easy to spoof. Use the parsed result for analytics heuristics and debugging, not as an authentication or security control.

Why use it

  • Identify the client behind an odd analytics or log entry.
  • Check which OS and browser a support report came from.
  • Recognise whether a request came from a crawler or a script.

How to use it

  1. 1Paste a User-Agent string, or start from a sample.
  2. 2Read the browser, OS, engine and device fields.
  3. 3Check the bot flag and the raw string length.
  4. 4Copy the parsed JSON for a bug report.

Worked examples

Chrome on Windows

Input

Mozilla/5.0 (Windows NT 10.0; Win64; x64) … Chrome/131.0.0.0 Safari/537.36

Output

Chrome 131, Windows 10 or 11, desktop, Blink engine, not a bot.

Command-line client

Input

curl/8.7.1

Output

curl, device type bot, flagged as automated.

Common mistakes

  • Blocking a client solely because its UA looks unusual; legitimate browsers and privacy tools alter the string.
  • Assuming a bot label proves intent; crawlers can claim to be Googlebot without verification.
  • Treating the OS version as exact when the string reports compatibility tokens rather than the real version.

Frequently asked questions

Can a User-Agent be trusted?
No. It is a header supplied by the client and can be changed freely. Verify crawlers by IP or reverse DNS when it matters.
Why is the Windows version “10 or 11”?
Windows 11 still reports Windows NT 10.0 for compatibility, so the UA alone cannot distinguish it from Windows 10.
Does it detect every bot?
No. It matches a list of known patterns. Unknown automation can pass as a normal browser.
Is the string sent anywhere?
No. Parsing is local.

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