Links are the connective tissue of the web. They guide users to content, help search engines understand structure and distribute authority across pages. When links fail, everything from user trust to search visibility can suffer. This is where a URL checker becomes essential. A URL checker is more than a quick "does this page load?" tool. At its most basic level, it confirms whether a URL resolves successfully. At a deeper level, it reveals status codes, redirect chains, DNS issues and server errors that aren't obvious from simply clicking a link.