Input
Result
The result will appear here.Your runs
Only runs that cost points are saved.
Sign in to keep a history of your runs.
User-Agent strings are an accumulation of thirty years of compatibility lies — every browser claims to be Mozilla, and most claim to be several others. This resolves one into the browser, rendering engine, operating system and device it actually describes, which is what you need when reading an access log or reproducing a bug from a support ticket.
How it works
- Parsing runs in your browser on ua-parser-js, the library most analytics tooling uses.
- Browser, engine, OS, device type and CPU architecture are reported separately.
- Your own User-Agent is filled in by default, so the tool is useful without pasting anything.
Where your data goes
Nowhere. This tool runs entirely in your browser: the text you paste is processed by the page and is never transmitted to a server or written to a log.
When a run costs points, a one-line summary is saved to your own history so you can find it again. The summary records the shape of the run — sizes, counts, the values you looked up — never the content you pasted.
What it costs
This tool is free, with no sign-in and no points.
Common questions
- Why does every browser say Mozilla?
- Nineties servers sniffed for Mozilla before serving frames, so every competitor claimed to be it, and nothing has ever been able to stop claiming it since. The token carries no information today.
- Should I use the User-Agent for feature detection?
- No. Test for the feature itself. UA strings are freely spoofed, increasingly frozen by browsers on purpose, and wrong the moment a new version ships.
- Why is a modern Chrome UA so vague?
- Browsers are deliberately reducing the detail in the UA string to limit fingerprinting, moving specifics to Client Hints that a site must ask for.
The open-source behind it
This tool runs on faisalman/ua-parser-js, released under MIT. If you need the same behaviour inside your own program, that is the library to reach for.
faisalman/ua-parser-jsAlso known as
- user agent parser
- parse user agent
- ua parser
- browser detection
- user agent analyzer