What Asynchronous Code is: Unlike a synchronous code snippet, which relies on sequential loading (load time for your tracking code plus your website), asynchronous code uses parallel loading, so both occur simultaneously. Another key difference between traditional and asynchronous code is where it’s placed. The synchronous snippet is usually found at the bottom of your page, before the </body> tag, while asynchronous code is typically placed at the bottom of the <head> section of your HTML.
Why use Asynchronous Code? Because asynchronous code loads alongside your page, it may reduce your page’s load time and make for a better user experience.
This post is part of an ongoing Clickipedia series, defining all the terms you need to know for conversion rate optimization. Keep checking back each week to learn more, and don’t forget to check out the whole series.