The Magento page cache library contains a simple PHP reverse proxy that enables page content caching. There are two types of distinguished content: private and public.
The “private” content is being served for each user separately and represents the personalized data of a customer. E.g. shopping cart, wishlist, customer addresses, notification messages. This data should not be cached on the server side, and should not be shown to more than one user. The private content is stored on the client’s side by Customer Data JS component (
Magento_Customer/js/customer-data.js). However, this is a topic for another blog post. Today we will focus on the second content type – public content, or rather the cacheable content and its variations in terms of customer grouping.