Everything you need to know about WOFF2
WOFF2 (Web Open Font Format 2, .woff2) is the modern web font format - the successor to WOFF, finalized as W3C Recommendation in 2018. WOFF2 uses Brotli compression (Google's algorithm), producing files 30% smaller than WOFF and 50%+ smaller than raw TTF. It's the only web font format you should ship today.
How it works under the hood
- Brotli compression. WOFF2 uses Brotli (RFC 7932) which is dramatically more efficient than DEFLATE for typed data like fonts.
- Glyph table preprocessing. Beyond compression, WOFF2 reorders and deduplicates font tables before compression for even better ratios.
- Same TTF/OTF inside. Like WOFF, WOFF2 wraps TTF or OTF - the underlying glyph data is unchanged.
- Universal browser support. Chrome 36+, Firefox 39+, Safari 12+, Edge 14+. As of 2024, you can ship WOFF2-only and serve 99%+ of users.
Where you'll actually use it
- Modern web typography (default for new sites since 2018)
- Performance-critical pages where every byte matters
- Variable fonts on the web (WOFF2 supports v1.8 variable axes)
- CDN-distributed fonts (smaller files = faster TTFB)
How it compares to alternatives
WOFF2 vs WOFF: WOFF2 is 30% smaller. WOFF2 vs TTF/OTF: WOFF2 is 50%+ smaller. There's no reason to serve TTF/OTF for web use anymore.
Things that will trip you up
- IE11 doesn't support WOFF2 - if you still need IE11, ship WOFF as fallback (and reconsider supporting IE11 in 2026)
- Self-hosted fonts need correct MIME type: `font/woff2` (Apache often defaults to wrong type)
- `font-display: swap` prevents invisible text during font load - critical for performance
Test it yourself: Browser DevTools, `woff2_decompress` from Google's woff2 tools. Subset fonts with `pyftsubset` (fontTools) for further size reduction.