How to debug missing glyphs and tofu with the glyph inspector
- Step 1Reproduce the tofu — Note the missing character. Look up its Unicode codepoint (U+1F600 for 😀, U+0151 for ő, etc.).
- Step 2Search the inspector — Drop the production font, search for the codepoint. If absent, the font genuinely lacks the glyph — switch fonts or add a fallback.
- Step 3Add a fallback — If the glyph is genuinely missing, add a fallback font in your CSS font-family chain that does have the character. The browser walks the chain automatically.
Frequently asked questions
Why does the same character render differently across browsers?+
Different browsers use different font fallback chains for missing glyphs. Safari might fall back to Apple Color Emoji while Chrome falls back to Noto Color Emoji — visible difference even though both are 'fallback'.
How do I avoid tofu entirely?+
Audit your content for the codepoint range it actually uses. Subset your font to cover that range explicitly. Fall back to system fonts for unexpected characters via font-family chains.
What's a reasonable coverage threshold?+
Latin sites: 100% Latin Basic + Latin-1 Supplement + General Punctuation. Multilingual sites: explicit coverage for each supported language plus a fallback for the unsupported ones.
Privacy first
Every JAD Font tool runs entirely in your browser using opentype.js and the wawoff2 WASM Brotli encoder. Your fonts never leave your device — verified by zero outbound network requests during processing.