How to use the user agent parser
- The page opens with User-Agent string filled in with your own browser's string, and the cards show what it says.
- To check another string, paste it, or pick one under Try a sample, such as Googlebot smartphone, GPTBot or curl.
- Click Use my browser's User-Agent to return to yours, or Copy string to copy it.
- Read the six cards, from Browser to Bot or automated client. In Chrome and Edge a blue box adds exact Client Hints values.
How the string is read
The parser tests the string against ordered pattern lists, and the first match wins. Bots go first, so Googlebot smartphone, which also contains the word Chrome, is reported as Googlebot. Browsers follow in an order that avoids false matches: Edge before Chrome and Chrome before Safari, because each names the next. The operating system comes from tokens such as Windows NT 10.0, iPhone OS 18_6, Android 14 and Mac OS X. An iPad, or Android without the Mobile token, counts as a tablet. Nothing you paste is sent anywhere.
Why Windows 11 says Windows NT 10.0
Chromium reduces the User-Agent: minor, build and patch numbers become 0.0.0, Windows is always Windows NT 10.0, macOS is always 10_15_7, and Android is always Android 10; K. The exact values live in Client Hints, where a Windows platform version of 13.0.0 or higher means Windows 11. For your own browser the parser reads them. Firefox and Safari do not currently share them.
Worked example
Choose Chrome on iPhone under Try a sample, which fills the box with:
Mozilla/5.0 (iPhone; CPU iPhone OS 18_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/140.0.7339.101 Mobile/15E148 Safari/604.1
The cards then show:
- Browser: Chrome 140.0.7339.101
- Rendering engine: WebKit 605.1.15
- Operating system: iOS 18.6
- Device type: Mobile, Apple iPhone
- CPU architecture: Not stated in this string
- Bot or automated client: No
Chrome on an iPhone reports WebKit because Apple requires every iPhone browser to use it. The page opens with your own string, so your first result will differ.
Limits and edge cases
- Brave and other Chromium browsers look exactly like Chrome in the string.
- An iPad requesting the desktop site sends a Mac string. For your own device the parser spots the touch screen, but not for a pasted string.
- Device models appear as the code the device sends, such as SM-S918B. Chrome on Android hides even that.
- The bot list covers major crawlers, SEO tools, AI crawlers, link previewers and HTTP libraries. Other names ending in bot show as Unlisted bot.
Frequently asked questions
What is my user agent?
It is the line of text your browser sends to every website to name its browser, version and operating system. This page shows yours in the User-Agent string box when it opens. Click Copy string to copy it.
Why does my Windows 11 PC show Windows NT 10.0?
Chromium browsers freeze the operating system part of the string, so Windows 10 and Windows 11 both say Windows NT 10.0. The real version comes only from Client Hints, which this page reads for your own browser.
How can I tell if a visitor is a bot?
Look for a crawler name such as Googlebot or GPTBot, or a library such as curl. Names are easy to fake, so confirm a search crawler with a reverse DNS lookup on the visitor IP address, as Google and Bing document.
Can a user agent be faked?
Yes. Any browser, extension or script can send any User-Agent. Use it for statistics and layout hints, never for security or access control.
Why does every user agent start with Mozilla/5.0?
Early websites sent full pages only to browsers saying Mozilla, so every later browser copied the word. Chrome also names Safari, KHTML and Gecko for the same reason, which is why the string looks messy.
Related tools: the screen resolution checker for your display size, the HTTP status codes reference for what crawlers receive, and the IP subnet calculator for checking visitor addresses.