What Is My User Agent?
Your browser introduces itself to every website with this string. Here is yours, decoded.
What is a user agent?
Every time your browser loads a page, it sends a short text introduction called the user agent. It names your browser, its version, your operating system, and sometimes your device type. Websites use it to serve you the right layout, for example the mobile version of a page on a phone, and analytics tools use it to count which browsers people use.
Why does it matter for privacy?
The user agent alone does not identify you, but combined with other details like screen size, timezone and installed fonts it contributes to browser fingerprinting, a technique that tries to recognize you without cookies. If you use anti-detect setups or test how sites see different devices, checking the user agent is step one.
Can I change my user agent?
Yes. Chrome and Firefox both have developer tools and extensions that let you send a different user agent, which is useful for testing how your site looks on other devices. Some privacy extensions rotate it automatically. After changing it, reload this page to confirm the new string took effect.
Frequently asked questions
Is my user agent unique?
Probably not by itself. Millions of people share the same Chrome on Windows string. Uniqueness comes from combining many signals, not this one.
Does a VPN change my user agent?
No. A VPN hides your IP but your browser still sends the same user agent. They solve different problems.
Why do sites care about my user agent?
Mostly for practical reasons: showing the mobile layout on phones, warning about outdated browsers, and counting browser market share.