Don’t use runtime CSS-in-JS if you care about the load performance of your site. Simply less JS = Faster Site. There isn’t much we can do about it. But if you want to see some numbers, continue reading.

In this article, I will attempt to demystify the high-level strategies of the most popular CSS-in-JS libraries, discuss the performance issues they may introduce on occasion and finally consider techniques that we can employ to mitigate them.