User-Agent Switcher is a Firefox extension designed for web development and testing. This free tool allows users to change the User-Agent header of their browser, enabling them to simulate different browsers or devices. This feature is particularly useful for developers who need to test how their websites appear on various platforms or for users who encounter content restrictions based on their browser type. In addition to altering the User-Agent, it also modifies several navigator properties to enhance emulation accuracy.

The extension is equipped with a built-in Network Analyzer and allows users to view their current User-Agent header. It employs a bundled version of BrowsCap to facilitate seamless emulation of User-Agent values, ensuring a high level of accuracy without requiring extensive user configuration. Although primarily in maintenance mode, the extension remains a valuable resource for both developers and users seeking to navigate web content more flexibly.