# Webfont Format

> Use when reviewing stylesheets, component styles, and responsive behavior related to Optimize web font formats. Check the rendered layout across breakpoints and interaction states before proposing a fix.

- Skill: `thedaviddias/webfont-format` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add thedaviddias/webfont-format`
- Raw SKILL.md: https://api.skillmd.com/api/skills/thedaviddias/webfont-format/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: thedaviddias (https://skillmd.com/u/thedaviddias)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/thedaviddias/webfont-format

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# Optimize web font formats

Modern font formats reduce file sizes by 30-50%—directly improving page load speed and Core Web Vitals scores.

## Quick Reference

- Use WOFF2 as primary format (~30% smaller than WOFF)
- Include WOFF fallback for older browsers
- Apply font-display: swap for better perceived performance
- Preload critical fonts and subset to reduce file sizes

## Check

Verify that web fonts use modern formats (WOFF2, WOFF) with proper fallbacks and are optimized for performance with font-display and preloading strategies.

## Fix

Convert fonts to WOFF2/WOFF formats, implement proper font loading strategies, and optimize font delivery with compression and caching.

## Explain

Explain how modern web font formats reduce file sizes, improve loading performance, and provide better browser support compared to legacy formats.

## Code Review

Review stylesheets, component styles, and responsive states related to Optimize web font formats. Flag exact selectors, declarations, or breakpoints that violate the rule in the rendered UI.

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For full implementation details, code examples, and framework-specific guidance,
see `references/rule.md`.

Rule page: https://frontendchecklist.io/en/rules/css/webfont-format