What is a User-Agent?

User-Agent is a string describing a browser, compatible software, and possibly its operating system. JavaScript exposes it through navigator.userAgent.

How NetKarte shows it

You can inspect the current string in NetKarte's Browser card.

The Browser card displays navigator.userAgent as supplied. NetKarte also uses it for simple browser and OS classification. It is usually similar to the HTTP User-Agent header, but they are collected in different places.

How to read it

The string may contain several tokens such as Mozilla, AppleWebKit, Chrome, and Safari. This is a result of compatibility history and does not mean all named products are in use.

Notes

User-Agent can be spoofed and browsers may reduce its detail. It should not be used alone to identify a device or person, control access, or make a security decision.

Why several browser names appear

Chrome and Safari in one User-Agent do not mean two browsers are running. Compatibility tokens coexist. Compare the string with the browser's own version screen rather than picking one product name.

In NetKarte, compare the Browser card with HTTP User-Agent when useful. One comes from page JavaScript and the other from the server's received request; overrides and collection timing can matter. A mismatch alone is not evidence of an attack. When sharing the string for support, remember it can include OS and environment information.