Calculating individual page speed performance metrics can help you to understand how efficiently your site is running as a whole. Since Google uses the speed of a site (frequently measured by and referred to as PageSpeed) as one of the signals used by its algorithm to rank pages, it's important to have that insight down to the page level.
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One of the pain points in website performance optimization, however, is the lack of ability to easily run page speed performance evaluations en masse. There are plenty of great tools like PageSpeed Insights[3] or the Lighthouse Chrome plugin[4] that can help you understand more about the performance of an individual page, but these tools are not readily configured to help you gather insights for multiple URLs — and running individual reports for hundreds or even thousands of pages isn’t exactly feasible or efficient.
In September 2018, I set out to find a way to gather sitewide performance metrics and ended up with a working solution[5]. While this method resolved my initial problem, the setup process is rather complex and requires that you have access to a server.
Ultimately, it just wasn’t an efficient method. Furthermore, it was nearly impossible to easily share with others (especially those outside of UpBuild).
In November 2018, two months after I published this method, Google released[6] version 5 of the PageSpeed Insights API. V5 now uses Lighthouse as its analysis engine and also incorporates field data provided by the Chrome User Experience Report (CrUX). In short, this version of the API now easily provides all of the data that is provided in the Chrome Lighthouse audits[7].