Best practices for cache control settings for your website

Your browser, on each request to the website/resource, tries to load as little data as possible by reading cached information from local memory. This is only possible we provide enough instructions for the browser, to explain what resources it needs to keep and for how long.

These instructions function as directives; to tell your browser about them, you must add them to response HTTP header information. The most common directives involved in the cache process are “Cache-Control”, “Expires”, “Etag” and “Last-Modified”.

Etag is one of the cache settings. The main idea behind this HTTP header is to allow your browser to be aware of modifications to relevant resources without downloading full files.

The server could calculate something similar with hash sum of each file and then send this hash sum to the client. The next time the client tries to access this resource, instead of downloading the file, the browser will send something like this in the HTTP header: If-None-Match: W/“1d2e7–1648e509289”