Speed Up WordPress

Google Fonts is always a bottleneck for website performance. The Google Fonts' CSS is a render-blocking resource, which means that the browser won't render any processed content until the CSS is loaded. It also causes a blank space when the font is being loaded.

In the previous post of this series, I have shown you a way to get rid of these problems using a script from PerfPerfPerf. Since then, Google Fonts has some updates and the PerfPerfPerf's becomes outdated. And we need a better way to load Google Fonts now!

Google Fonts loading problems

Before going into the solution, let's summarize 2 issues, as they are the most important problems with Google Fonts. And these are the problems we're going to resolve in this article.

Google Fonts Render Blocking CSS

When Google Fonts is being loaded, no further content (text, images, CSS, JavaScript, etc.) is loaded. That means your whole page is blocked until Google Fonts finishes loading its CSS.

This problem is critical because it freezes your website when loading and increases the First Contentful Paint (FCP) of the page. FCP is an important, user-centric metric for measuring perceived load speed because it marks the first point in the page load timeline where the user can see anything on the screen—a fast FCP helps reassure the user that something is happening. It's a part of the Web Core Vitals and is an SEO factor. So if you have it high, your site might get a lower ranking.

Blank space while loading Google Fonts

Another problem with Google Fonts is that when it's being loaded, the text is completely vanished before your eyes. Only until it's finished loading, you can see the text. This effect is called FOIT (Flash Of Invisible Text).

That causes a really bad experience for your users. And if the loading time is huge, your users might think your website is broken (because they see nothing!).

And FOIT also affects the First Contentful Paint (FCP) as well, and thus might affect your search ranking.

How to fix Google Fonts problems

Load Google Fonts asynchronously

To solve the 1st problem of render-blocking, we need to load Google Fonts asynchronously. That means we'll load the Google Fonts' CSS without blocking loading or rendering other resources.

There are 2 solutions:

Preloading CSS with rel="preload"

preload is a mechanism to load resources without any effect on loading the other ones. It also puts a higher priority on the resources that are preloaded. That means these resources will be load before other resources. You can read more about this on MDN.

Let's assume you want to load Roboto font. Google gives you the HTML like this:

<link href="https://fonts.googleapis.com/css2?family=Roboto" rel="stylesheet">

To make the CSS preloaded, you need to change it to:

<link href="https://fonts.googleapis.com/css2?family=Roboto" rel="preload" as="style" onload="this.rel='stylesheet'">

The CSS is now preloaded. And when it finishes loading, it'll be applied.

The preload technique works well in all modern browsers.

Using media type

Another solution is using media type, which is supported by all browsers. This technique is created by Filament Group. The HTML markup is simple as follows:

<link href="https://fonts.googleapis.com/css2?family=Roboto" rel="stylesheet" media="print" onload="this.media='all'">

What it does is loads the CSS for the print-based media. In other words, the CSS is applied only when the users try to print the page. The loading process is now asynchronous (since we're on browsers). And when it's done, the CSS is applied for all media (which includes browsers).

I've been testing this technique for a while and see a good improvement in font loading. You can test on MetaBox.io and docs.metabox.io websites to see how it works.

Using font-display: swap

To solve the 2nd problem with a blank is when loading fonts, we need to use font-display: swap. Basically, it allows us to display the text first with a fallback font family (usually serif or sans-serif). And when the font is loaded, it swaps the text into the wanted font. This effect is called FOUT (Flash Of Unstyled Text). Unlike FOIT (Flash Of Invisible Text), users still see the text while the font is loaded. So, the user experience is better. And also the FCP (First Contentful Paint) is lower.

The good news is Google Fonts now supports font-display: swap by default. You can see it in the font URL like this:

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

Notice the display=swap in the URL. The CSS loaded for the font will have font-display: swap.

This technique works in all modern browsers, and it's safe to use.

Just a note that the solution in the 1st part of this series, which uses PerfPerfPerf script, tries to add font-display: swap to the Google Fonts' CSS. It's not needed anymore.

So the final code to load Google fonts now is either of these:

<link href="https://fonts.googleapis.com/css2?family=Roboto&display=swap" rel="preload" as="style" onload="this.rel='stylesheet'">
<link href="https://fonts.googleapis.com/css2?family=Roboto&display=swap" rel="stylesheet" media="print" onload="this.media='all'">

Apply Google Fonts loading techniques in WordPress

The best way to apply the techniques above is adding the code into your theme's header.php file. Or you can create a child theme and modify the header.php file. So your header.php file will look like this:

<!doctype html>
<html <?php language_attributes(); ?>>
<head>
    <meta charset="<?php bloginfo( 'charset' ); ?>">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link href="https://fonts.googleapis.com/css?family=Roboto&display=swap" rel="stylesheet" media="print" onload="this.media='all'">
    <?php wp_head(); ?>
</head>
// Other code

I find it's harder to do this if you use page builders. You need to disable default Google Fonts and apply the code above. The only plugin I found that disables the Google Fonts is Autoptimize. Unfortunately, it removes our manual link tag, too.

The best solution for page builders is using Autoptimize to preload the Google Fonts. You can turn it on the settings page:

You can see it in action on GretaThemes website.

Conclusion

After applying the new techniques to our websites, I'm quite happy with the result. The loading speed is increased and the FOUT effect is minimal. Users probably don't notice the font change (swapping). And of course, the Google PageSpeed Insights score is higher than before (in my test for MetaBox.io's homepage, it has 100 scores for desktops).

I think optimizing the loading speed for Google Fonts is very important for both users and search engines. And you should do it now. Feel free to discuss this with us on the Facebook group, or leave a comment below.