Käyttäjäagenttitunniste

Käyttäjäagenttitunniste, often referred to as a user-agent string, is a small piece of text that a web browser or other client application sends to a web server with each request. This string identifies the client software, its version, operating system, and sometimes other details about the user's device and configuration.

The primary purpose of a user-agent string is to allow web servers to tailor their responses. For example, a server might send a different version of a webpage to a mobile browser compared to a desktop browser, or it might send optimized content based on the browser's rendering capabilities. This helps ensure a consistent and functional user experience across a wide range of devices and software.

User-agent strings are typically composed of several tokens separated by spaces. Common components include the browser name and version (e.g., Chrome/120.0.0.0), the operating system (e.g., Windows NT 10.0), and sometimes additional information about rendering engines or plugins. The exact format can vary significantly between different browsers and applications.

While useful for personalization and analytics, user-agent strings can also pose privacy concerns. Because they can uniquely identify a user's device and software, they can be used for tracking users across different websites. To mitigate this, some browsers and users attempt to modify or spoof their user-agent strings to enhance privacy. However, this can sometimes lead to compatibility issues, as some websites may not function correctly if they receive an unexpected user-agent string.