Ensure text remains visible during webfont load

Published on Updated on

Translated to: Español, Português, 한국어, Pусский

Fonts are often large files that take awhile to load. Some browsers hide text until the font loads, causing a flash of invisible text (FOIT).

How the Lighthouse font-display audit fails

Lighthouse flags any font URLs that may flash invisible text:

A screenshot of the Lighthouse Ensure text remains visible during webfont loads audit

See the Lighthouse performance scoring post to learn how your page's overall performance score is calculated.

How to avoid showing invisible text

The easiest way to avoid showing invisible text while custom fonts load is to temporarily show a system font. By including font-display: swap in your @font-face style, you can avoid FOIT in most modern browsers:

@font-face {
font-family: 'Pacifico';
font-style: normal;
font-weight: 400;
src: local('Pacifico Regular'), local('Pacifico-Regular'),
url(https://fonts.gstatic.com/s/pacifico/v12/FwZY7-Qmy14u9lezJ-6H6MmBp0u-.woff2)
format('woff2');
font-display: swap;
}

The font-display API specifies how a font is displayed. swap tells the browser that text using the font should be displayed immediately using a system font. Once the custom font is ready, it replaces the system font. (See the Avoid invisible text during loading post for more information.)

Preload web fonts

Use <link rel="preload" as="font"> to fetch your font files earlier. Learn more:

Google Fonts

Add the &display=swap parameter to the end of your Google Fonts URL:

<link
href="https://fonts.googleapis.com/css?family=Roboto:400,700&display=swap"
rel="stylesheet"
/>

Browser support

It's worth mentioning that not all major browsers support font-display: swap, so you may need to do a bit more work to fix the invisible text problem.

Codelab

Check out the Avoid flash of invisible text codelab to learn how to avoid FOIT across all browsers.

Stack-specific guidance

Drupal

Specify @font-display when defining custom fonts in your theme.

Magento

Specify @font-display when defining custom fonts.

Resources

Updated on Improve article

We serve cookies on this site to analyze traffic, remember your preferences, and optimize your experience.