By Shad Super in Questions —

What Are the Best Practices for Preloading Key Assets to Minimize First Contentful Paint (FCP) Time and Improve Page Speed?

Summary

The First Contentful Paint (FCP) is a performance metric that measures how long it takes for the browser to render the first piece of DOM content after a user navigates to your page. To minimize the FCP time and enhance page speed, several best practices such as asset preloading, effective usage of HTTP/2, critical HTML, CSS and JavaScript inlining, and font optimization can be implemented.

Asset Preloading

Using <link rel="preload"> tag can help you specify resources that need to be loaded with high priority. This can make important resources load earlier and be available as soon as they are needed [Preload Key Requests, 2021].

Effective Usage of HTTP/2

HTTP/2 Server Push

This technique can help in sending critical resources to the user even before the browser has asked for them, reducing valuable network round trips. However it should be used judiciously, as unwanted or excessive usage can harm performance [HTTP/2: The Next Version of the Internet, 2016].

Critical HTML, CSS, and JavaScript Inlining

Inlining

Inlining can minimize the amount of files the browser needs to download before it can start rendering the page. However, it should be used judiciously for key assets only. Otherwise, it can bloat the HTML and block the first paint [Inline Critical CSS, 2020].

Font Optimization

Using <link rel="preconnect"> informs the browser that your page intends to establish a connection to another domain, and that you'd like the process to start as soon as possible [Preconnect to required origins, 2021].

font-display property

Using the font-display property in your @font-face style allows you to control how web fonts are loaded and what happens when they're not available during the first paint [Ensure text remains visible during webfont loading, 2021].

Conclusion

To achieve a faster FCP, you should preload key assets, effectively use HTTP/2, consider inlining critical HTML, CSS, and JavaScript, and optimize your web fonts. This will enhance your users' experience by improving your page speed.

References