The User Agent Switcher changes your user agent to spoof other devices and/or browsers. You can put on your IE hat and slip past virtual bouncers into Internet Explorer-only websites; blend in as an iPhone or see how sites render when they think you're Google's search spider. User-Agent Switcher is simple, yet powerful. It adds a toolbar button that you can use to toggle between different commonly used user agent strings, or you can enter your own. User Agent Switcher overrides Chrome's default user agent, tricking websites into thinking you’re using a different browser. What’s a User Agent? A user agent is a small text description of your device that is sent with every web request. Websites can detect the browser you’re using and serve different content - this is why iPhone and Android users see special mobile websites when they browse the web.