WOFF (Web Open Font Format) is a font format specifically designed for use on web pages. It is essentially a compressed TrueType or OpenType file with additional metadata, optimized for faster loading over the network. WOFF is a W3C recommendation and is supported by all modern web browsers, allowing designers to use custom typography on their websites (web fonts). Sample WOFF files are used to test web browser font rendering and performance. Developers use them to verify that fonts load correctly via CSS @font-face rules and that fallback fonts are displayed properly while the web font is loading. They are also used to benchmark decompression speeds and to test CORS (Cross-Origin Resource Sharing) policies for font resources.