Dries Buytaert

Explanation

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.

Used to promote alternative communication protocols through which the same resource can be retrieved.
h2 stands for HTTP/2 over TLS. The browser and server can decide to upgrade from HTTP/1.1 to HTTP/2 over TLS.
h2c stands for HTTP/2 over TCP. The browser and server can decide to upgrade from HTTP/1.1 to HTTP/2 over TCP.

Specifies whether the network connection stays open after the current request. keep-alive specifies that the browser would like to keep the connection open, while close indicates that the browser wants to close the connection.

The date and time at which the origin server believes the page was last modified.
Notice According to the Last-Modified header the site's content was changed less than ten minutes ago. If that is not the case, consider fixing your Last-Modified headers to improve caching.
Notice Because there is an Etag header, Last-Modified is likely to be ignored. The ETag hash is more accurate than the date/time in Last-Modified. Consider removing Last-Modified to save bandwidth and processing power.

A unique identifier that changes every time a page at a given URL changes. It acts as a fingerprint. A cache can compare Etag values to see if the page has changed and became stale. For example, a browsers will send the ETag value of a cached page in an If-None-Match header. The web server compares the ETag value sent by the browser with the ETag value of the current version of the page. If both values hasHeaderWithName, the web server sends back a 304 Not Modified status and no body.

Used by the server to advertise its support of partial HTTP requests. The browser can ask for a range or subset of the response body. It's a feature that allows a browser to resume an interrupted download. bytes is the only range unit currently supported. none means that the server does not support range requests.

The size of the message body, in bytes.

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

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 Cross-Origin-Resource-Policy header to specify who can load this page.

missing Add a X-Frame-Options header. The X-Frame-Options header prevents this URL from being embedded in an iframe. This protects against clickjacking attacks. Alternatively, set a Content-Security-Policy header with a frame-ancestor directive.

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