Cache-Control

The Cache-Control HTTP header field holds directives (instructions) — in both requests and responses — that control caching in browsers and shared caches (e.g. Proxies, CDNs).

Clear-Site-Data

The Clear-Site-Data header clears browsing data (cookies, storage, cache) associated with the requesting website. It allows web developers to have more control over the data stored by a client browser for their origins.

Content-Type

The Content-Type representation header is used to indicate the original media type of the resource prior to any content encoding applied before transmission.

Date

The Date general HTTP header contains the date and time at which the message originated.

Expires

The Expires HTTP header contains the date/time after which the response is considered expired. Invalid expiration dates with value 0 represent a date in the past and mean that the resource is already expired. Note: If there is a Cache-Control header with the max-age or s-maxage directive in the response, the Expires header is ignored. Format Expires: <http-date> More info on: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Expires

Server

The Server header describes the software used by the origin server that handled the request — that is, the server that generated the response.

Strict-Transport-Security

The HTTP Strict-Transport-Security response header (often abbreviated as HSTS) informs browsers that the site should only be accessed using HTTPS, and that any future attempts to access it using HTTP should automatically be converted to HTTPS. max-age=<expire-time> The time, in seconds, that the browser should remember that a site is only to be accessed using HTTPS. includeSubDomains Optional If this optional parameter is specified, this rule applies to all of the site's subdomains as well. preload Optional Non-standard See Preloading Strict Transport Security for details. When using preload, the max-age directive must be at least 31536000 (1 year), and the includeSubDomains directive must be present. Not part of the specification.

Vary

The Vary header in HTTP is used to indicate that the response varies based on the value of certain headers in the request. The Vary header value can be a comma-separated list of headers that the response varies based on. Here's a similar validator for the Vary header