1.5 Performance & Core Web VitalsLowInferred

Fonts without font-display: swap

Without font-display set, the browser can hide text while a web font loads, the flash of invisible text. Using swap shows fallback text immediately and swaps the font in when ready.

What it is

Flash of invisible text during font load.

Why it matters

Delays text visibility (UX, perceived LCP).

How to fix it

Use font-display: swap/optional.

How to find it on your site

  1. Check the font-face rules or font loading config for font-display.
  2. Watch the page load for any flash of invisible text.
  3. Set font-display: swap, or optional, on web fonts.
  4. Re-test that text is visible immediately on load.

Cross-reference to ranking and citation factors

Visible text sooner improves perceived load and avoids layout shift from late fonts, supporting both LCP and CLS.

Impact

Low. Inferred.

Evidence

font-display improves perceived load. web.dev, Core Web Vitals (Google)

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