Overview

font/woff is the media type for web fonts compressed with Web Open Font Format 1.0. It wraps TrueType/OpenType glyph data for web delivery and is used when loading web fonts via @font-face.

Details

WOFF is essentially a container that adds zlib compression and metadata over TTF/OTF outline data. Historically several labels existed such as application/font-woff, but RFC 8081 introduced the top-level `font` type, making font/woff canonical. Being already compressed, transport-layer gzip yields nothing.

The most common real-world pitfall with web fonts is CORS. Unlike stylesheets, fonts are subject to CORS rules for cross-origin requests, so loading fonts from another domain (or CDN) requires the server to send `Access-Control-Allow-Origin` for the browser to use the font. Without the header, the font silently fails to load and falls back to a system font. Since fonts rarely change, grant a long cache lifetime.

Syntax

e.g. Content-Type: font/woff

File extensions

Notes

• Cross-origin fonts require an Access-Control-Allow-Origin (CORS) header — without it the font is not applied and falls back.
• WOFF2 compresses better (roughly 30%+ smaller), so prefer WOFF2 on supporting browsers with WOFF as fallback.
• Already-compressed, so transport gzip is pointless, and a long max-age cache (like favicons) is appropriate.

Related types

Related headers