Favicon.

The name comes from 'favourite icon': originally the icon only appeared in Internet Explorer's list of favourites. Today it shows up in many more places: in the browser tab, in the history list, as an app icon when someone adds the website to the iPhone home screen, and on smartphones directly next to the result in Google search. That makes the favicon one of the few brand elements someone sees before they have even opened the website.

Technically, a clean favicon set today consists of a few files: a favicon.ico for older browsers and tools, an SVG or PNG version for modern browsers, an apple-touch-icon of 180 × 180 pixels for iOS and icons for the web app manifest (typically 192 and 512 pixels). They are linked in the head section of the page or, with frameworks such as Next.js, via convention files in the app directory. For Google search, according to Google's documentation, the favicon must be square, have a side length that is a multiple of 48 pixels and be fetchable by Googlebot.

In design terms, the favicon is a task of its own, not a scaled-down copy of the logo. A word-and-figure mark with company name and tagline becomes a grey smudge at 16 pixels. A reduced symbol works better: a letter, a shape or the logo's figurative mark, with enough contrast on light and dark backgrounds. iOS adds a particularity: the system rounds the corners itself and fills transparent areas with black, so app icons for the home screen should be created edge to edge and without transparency.

What counts most for the effect is consistency. A missing favicon shows a generic globe icon in the tab and a placeholder in mobile search; both look unfinished. A favicon that does not match the rest of the corporate design gives away recognition exactly where twenty tabs are open side by side. The effort is small, so it belongs on the acceptance checklist of every project.