One page optimization means one version of a page from your website (one URL) to be optimized by NitroPack once.
When this page version is optimized and stored in a local cache, no further optimizations are required, so this already-optimized page is directly served to your visitors. Visits on optimized pages are not counted as new optimizations unless the cache is purged or invalidated.
Purging or invalidating the cache clears the optimized pages cache, hence new page optimizations need to be performed by NitroPack.
What is a Page Version?
A page version is a single page loaded with a different set of cookie values or loaded from a different device type (mobile, tablet, or desktop).
If the same page gets loaded with another set of cookies or device type, then the content is different. We consider this another version of the same page.
An example for a page version is a single URL, both in English and German (two languages). The content in both cases is different, so it requires two separate page optimizations. One optimization is for the English version, and another for the German version of the same page URL.