Broken Link Checker is a Firefox extension designed to help web developers and IT professionals identify broken links on webpages. This subscription-based tool scans the current page and all its sub-frames, checking for broken links (404 errors) and redirects (301, 307, 308 codes). It categorizes broken links for easy detection and provides a focus feature for quick navigation. The extension operates efficiently by evaluating five links simultaneously and can be displayed in a popup or embedded within the page.

In addition to its primary function, Broken Link Checker includes features for deep searching within a website, allowing users to parse all links of the same domain. Users can also filter out URLs based on specific keywords to streamline the process. Furthermore, it extracts links embedded in text that are not actual hyperlinks and provides filters to display links based on their HTTP status codes, making it a comprehensive tool for maintaining website integrity.