A favicon checker finds the icons a website uses in browser tabs, bookmarks and search results, and checks that they are declared properly. Enter a URL and this tool reads the page's <head>, lists every <link rel="icon"> declaration (including shortcut icon and apple-touch-icon) with its declared size and type, and previews each icon.
It flags three common gaps: no favicon link at all (browsers then fall back to /favicon.ico at the site root), no Apple touch icon for iPhone and iPad home screens, and no 192×192 or 512×512 PNG icons for Android and installed web apps. An icon that fails to load disappears from the preview, which is a quick sign of a broken path.
Limits: the tool reads the HTML before JavaScript runs and doesn't open the web app manifest, so icons declared only in site.webmanifest are not listed. It doesn't check whether /favicon.ico exists or measure the real size of each file; it reports the sizes the tags declare.