What is a user agent?
Every time your browser requests a web page, it sends a short text called the user agent string. It tells the website which browser, version, operating system and type of device you are using, so the site can send a page that works well. For example, a typical Chrome on Windows user agent looks like Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/… Safari/537.36.
How to use the checker
- Open the page: your own browser details are detected automatically.
- Copy your user agent when a support team or developer asks for it.
- To decode another user agent, for example from a server log or analytics report, paste it into the box.
Why are user agents so confusing?
Almost every user agent starts with "Mozilla/5.0" and mentions several browsers. This history comes from the 1990s, when websites sent better pages only to Netscape (codenamed Mozilla). Other browsers copied its name to get the same pages, and each new browser kept adding names to stay compatible. That is why Chrome's user agent mentions Safari and Gecko, and Edge's mentions Chrome.
Detected details explained
- Browser: the name and version, such as Chrome, Edge, Firefox, Safari, Samsung Internet or Opera.
- Operating system: Windows, macOS, Android, iOS, ChromeOS or Linux. Windows 10 and 11 send the same "NT 10.0" code; supported browsers can tell them apart using "client hints", which this tool uses when available.
- Rendering engine: Blink (Chrome, Edge, Opera), WebKit (Safari and every browser on iPhone) or Gecko (Firefox).
- Device type: mobile, tablet or desktop, estimated from keywords in the string.
Should you rely on user agents?
For website development, detecting features (for example, "does this browser support WebP?") is more reliable than reading user agents, because browsers increasingly reduce the detail they share for privacy. User agents remain useful for analytics, troubleshooting and support.
Frequently asked questions
Can a user agent be faked?
Yes. Browsers and extensions can change it, and some bots pretend to be normal browsers.
Does the user agent identify me personally?
No, but combined with other details it can contribute to "fingerprinting". Modern browsers are reducing this information.
How do I find my screen resolution?
Use the Screen Resolution Checker.