Caching refers to the process of storing data in a cache (temporary storage area). When someone requests the data, it is fetched from the cache.
contentstack-express stores the entire content of the rendered page. The visitors are then served the cached version of the content, instead of rendering pages every time. This decreases the number of read requests sent to the database, as well as improves the overall performance of the website.
To enable content caching, you need to set cache to “true” in the config.