User Agent Parser: step by step
- Paste a user agent string into the box. Your own is filled in to start with.
- Read the browser, engine, OS and device underneath.
- Paste several lines to decode them one after another.
Reading a user agent string
A user agent is the line your browser sends with every request to say what it is. It's messy for historical reasons: almost every browser still starts with Mozilla/5.0, and Chrome-based browsers mention Safari too. The parser reads the parts that matter:
| Part | Example | Means |
|---|---|---|
| Platform | (Windows NT 10.0; Win64; x64) | Windows 10 or 11, 64-bit |
| Platform | (iPhone; CPU iPhone OS 18_0 like Mac OS X) | iPhone on iOS 18 |
| Engine | AppleWebKit/537.36 (KHTML, like Gecko) | WebKit or Blink |
| Browser | Chrome/141.0.0.0 | Chrome version 141 |
| Browser | Edg/141.0 or OPR/115 | Edge or Opera, built on Chrome |
Where to find user agents to check
- Web server and CDN access logs (Apache, Nginx, Cloudflare).
- Analytics exports and bug reports from users.
- Your own browser: see What Is My User Agent.
Why versions look frozen
Modern browsers reduce the detail they share for privacy, for example always reporting Windows NT 10.0 even on Windows 11, and Mac OS X 10_15_7 on newer macOS. For exact details, sites use Client Hints instead.
Frequently asked questions
Can it detect bots?
Yes. Common crawlers like Googlebot, Bingbot, GPTBot and others are flagged, along with generic signs like "bot", "spider" and "crawl".
How accurate is it?
Very good for mainstream browsers and systems. User agents can be faked, though, so treat them as a hint rather than proof.
Updated