User-Agent Parser identifies the browser, operating system, and device type from a given user-agent string. Every visitor’s request includes a user-agent header, which can reveal whether they’re on mobile, desktop, or a crawler. By analyzing this data, you can adapt content or troubleshoot compatibility issues. For example, ensuring old IE versions receive polyfills or that certain crawlers are recognized. This tool is handy for logging or analytics, especially if you notice unusual user-agents. Marketers can confirm if traffic is truly from real browsers or disguised bots, improving web analytics accuracy and site performance optimization.