What Does User Agent (UA) Mean?
A user agent (UA) is a software element that acts on behalf of a user. However, the term user agent has also come to be associated with a header string in HTTP and related technologies that help a hosting server identify the type of operating system and/or device requesting content.
Techopedia Explains User Agent (UA)
A broader UA definition includes Web crawlers, Web bots and other technologies. However, a Web browser is a simple example of a common UA setup. Here, the browser acts as the UA, where the user actively controls the browser. The browser issues certain UA strings that show the specific technology used to access a site, page or other content. For example, a UA string from a Firefox browser would include the word Mozilla, as well as version data and other details.
