User Agent Parser
Read the browser, engine, operating system, device and bot flags from any UA string.
Decode a User Agent String
The user agent string is a monument to compatibility hacks. Chrome on Windows announces itself as Mozilla, AppleWebKit, KHTML, Gecko and Safari before ever mentioning Chrome — each of those a lie added to get past some site’s browser sniffing, then kept forever because removing it would break things.
This parser untangles it into the fields you actually want, and shows your own browser’s string alongside. It also flags the modern wrinkle: browsers are now freezing and reducing these strings deliberately, so detection based on them is less reliable every year.
Key features
- Browser and version — including the ones that hide behind other names in the string.
- Engine identified — Blink, WebKit or Gecko, which is what actually determines behaviour.
- Operating system and version — including the frozen values recent browsers report.
- Device type — desktop, mobile, tablet or bot, inferred from the available tokens.
- Your own UA shown — one click to inspect what your browser is sending.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: User Agent Parser
- Paste a user agent string
From a server log, an analytics export, or a bug report. - Or load your own
One button fills in what this browser is currently sending. - Read the breakdown
Browser, engine, OS, device type and the raw tokens they came from. - Check the caveats
Anything uncertain or frozen is flagged rather than reported as fact.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Developer |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
Why does Chrome claim to be Safari and Mozilla?
Historical accident compounded by necessity. Sites sniffed for Mozilla, so everyone claimed it; sites sniffed for Safari once WebKit mattered, so Chrome claimed that too. Each token was added to avoid being locked out, and none can now be removed safely.
Why does the OS version look wrong?
Because browsers are freezing it. Chrome reports Windows 10 for Windows 11, and macOS versions stopped advancing past 10.15 in the string. This is deliberate anti-fingerprinting, and it means UA-based OS detection is now approximate at best.
Should I use user agent detection in my site?
Rarely. Feature detection — checking whether the capability exists — is more reliable and does not break when a browser changes its string. Reserve UA parsing for analytics and for working round specific known bugs.
Can a user agent string be faked?
Trivially. It is a header the client sets, and any browser extension, script or command-line tool can say whatever it likes. Never treat it as a security signal.