Dries Buytaert

Explanation

A Cross-Origin Resource Policy (CORP) header specifies the origins that are allowed to read this page.

• cross-origin specifies that any origin can read this page. This is the default option and the least safe.
M
• same-origin specifies that only requests from the same origin can read the resource. This is the most strict and safest option.
• same-site specifies that only requests from the same site can read the page. Is a bit more relaxed than same-origin as it allows different subdomains, schemes and ports.

Notice cross-origin should be avoided if possible, but is sometimes necessary to support third-party CDNs.

The type of the message body, specified as a MIME type.

The date and time at which the request was made. A browser uses it for age calculations rather than using its own internal date and time; e.g. when compairing against Max-Age or Expires.

Some of the software used to generate or serve this page.
Warning Sharing too many details about a server or web application makes it easier for hackers to target a website. Avoid specific version numbers such as 1.0, especially when running software that is end-of-life and/or has known security bugs. Consider removing this header. At a miminum, remove details version numbers.

The size of the message body, in bytes.

Notice It is recommended to use Content-Security-Policy instead of X-XSS-Protection. Some browsers like Firefox refuse to support X-XSS-Protection. Content-Security-Policy is more advanced, a W3C recommendation, and supported by all modern browsers.

X-Frame-Options prevents this URL from being embedded in an iframe. This protects against clickjacking attacks.
sameorigin means that this page can be displayed in a iframe, but only on the currrent origin. It can't be displayed on another domain. Consider setting this to deny for added security.

Used to promote alternative services through which the same resource can be retrieved.
h3 stands for HTTP/3. The number after the dash indicates the draft; e.g. h3-27 would be draft 27 of the HTTP/3 protocol.
ma is the number of seconds the alternative service is considered fresh.

missing Add a Strict-Transport-Security header. The Strict-Transport-Security header or HSTS header is used to instruct browsers to only use HTTPS, instead of using HTTP. It helps enforce secure communication.

missing Add a Content-Security-Policy header. The Content-Security-Policy header helps browsers prevent cross site scripting (XSS) and data injection attacks.

missing Add a Referrer-Policy header. When a visitor navigates from one page to another, browsers often pass along referrer information. The Referrer-Policy header controls how much referrer information a browser can share. This is important to configure when private information is embedded in the path or query string and passed onto an external destination.

missing Add a Permissions-Policy header. Restrict access to device features like the camera, microphone, location, accelerometer and much more.

missing Add a Cross-Origin-Embedder-Policy to specify how this page can be loaded by cross-origin resources.

missing Add a Cross-Origin-Opener-Policy header to opt-in into better browser isolation.

missing Add a X-Permitted-Cross-Domain-Policies header to prevent Flash, Adobe Reader and other clients from sharing data across domains.