Resource Domain Checker is a free Chrome add-on designed to help users identify all external domains loaded by a webpage. This tool captures various resource requests, including JavaScript, CSS, and asynchronous calls, providing a thorough overview of a website's network activity. It automatically filters out duplicate entries and organizes the results in an easy-to-read format, making it simple for users to understand the domains involved in a webpage's functionality.

The add-on features a language toggle that allows seamless switching between English and Japanese, catering to a broader audience. Users can quickly access the list of domains by clicking the NatchBurger icon in the toolbar and hitting the 'Get Domains' button. With a focus on privacy, the tool ensures that all data remains within the browser, offering a straightforward way to analyze web requests without compromising user information.