When you browse the web, your browser sends information to every website you visit. This information includes your IP address, browser and device type, operating system, and  your User Agent. Your User Agent is a string of text that identifies both your browser and your operating system. It’s like a fingerprint—unique to your specific setup.

The user agent string contains information about your browser, operating system, and sometimes your device. This information is used by websites to customize the content they serve up to you. For example, if a website sees that you're using an older browser, it might send you a simplified version of the site.

User agent checker is a tool that enables you to check whether the user agent string of your browser is being correctly reported. User agent strings are used by web servers to identify the browser and operating system you are using, and this information is then used to deliver the correct content and format for the page you are viewing. The user agent checker tool will tell you if the user agent string your browser is sending is accurate, and if not, what it should be. This can be useful for troubleshooting website problems, or for checking whether your browser is being correctly identified by websites.