User agent strings

Definition of a user agent string and some examples

When any user sends a request to access a web application, the web browser sends a HTTP Header called the user agent. The user agent string contains information about the user’s web browser name, operating system, device type, and other information.

The common format for a user agent string is:

User-Agent: <product> / <product-version> <comment>

This varies among different browsers. Here are some examples of user agent strings:

Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:47.0) Gecko/20100101
      Firefox/47.0
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like
    Gecko)