Monitoring speed and performance

Before we can start improving the performance of our site, we need to understand how fast our site is loading and where there might be opportunities for improvement. Without these tools, you’re just guessing what will speed up your store, and you’ll waste a lot of your time. You should also use these tools to track each change you make to ensure it actually speeds up your store.

In this book, we’re going to use GTmetrix. GTmetrix is a free tool that shows you exactly how fast your page loads and it also shows where any speed issues might come from. We’re going to create a baseline, test changes, look into waterfall data, and finally, set up periodic reports.

Since the first version of this book was published, PageSpeed Insights (https://pagespeed.web.dev/) has released a minimalistic yet powerful, and free, tool to monitor your page speed. You’re welcome to use this tool instead of GTmetrix, although later in...