Dries Buytaert

Explanation

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

The Accept-CH header specifies HTTP Client Hints that the server requests from the client (typically a browser) to optimize content delivery.

• sec-ch-ua: Requests a condensed version of the user agent string.
• sec-ch-ua-mobile: Requests a boolean hint indicating if the client's device is mobile.
• sec-ch-ua-platform: Requests the operating system platform of the client's device, such as Windows or MacOS.
• sec-ch-ua-arch: Requests the client's device CPU architecture, such as ARM or x86.
• sec-ch-ua-full-version-list: Requests a detailed list of version numbers for the client's browser and its significant components.
• sec-ch-ua-model: Requests the model of the client's device.

private means the response can only be stored by the browser's cache, but not by CDNs, proxies, or any other shared caches.
no-cache means the response can be stored by any cache, but the stored response must be validated with the origin server before each reuse. If the origin confirms that the response hasn't changed, downloading of the full response body can be skipped.
Warning no-cache will cause a revalidation request to the origin server for every use of the cached response. Consider using public with appropriate max-age to improve caching efficiency.
Warning no-store means the response may not be stored in any cache, including the browser's cache.
max-age=0 with must-revalidate means caching is disabled and all requests must be validated with the origin server.
Notice It does not make sense to set must-revalidate with no-store; when nothing is cached, there is nothing to revalidate.
Notice It does not make sense to set must-revalidate with no-cache; must-revalidate is implied.
Notice no-store is set, so it does not make sense to set no-cache as well.
Notice no-store is set, so it does not make sense to set private as well.

Warning The page can't be cached by any shared caches such as Varnish or a CDN. If the page is something everybody can access, this behavior is not desired.
Notice Pragma is a HTTP/1.0 header. This request uses HTTP/1.1. In HTTP/1.1, Pragma is deprecated and superseded by the Cache-Control header. Remove Pragma to save bandwidth and processing power.

Indicates whether a browser can expose the request's credentials, including cookies and authorization headers, to frontend JavaScript code.

Specifies which headers can be exposed to the client in a CORS (Cross-Origin Resource Sharing) context.

Indicates whether a browser can share this resource with other code. * is a wildcard. It means the browser will allow code from any origin to access this resource.

A cookie that was sent from the server to the browser.
max-age= sets the maximum lifetime of the cookie in seconds.
domain= sets the domain to which the cookie will be sent.
path= indicates the path that must exist in the requested URL for the browser to send the cookie.
Notice samesite=lax instructs the browser not to share the cookie with third-party sites (e.g. when loading images, videos or frames from other sites), with one exception. The cookie will be sent when a user is navigating to the origin site from an external site (for example, when following a link). To improve protection against cross-site request forgery attacks, set to samesite=strict.
secure instructs the browser to only send the cookie back when HTTPS requests are used, making it more resistant to man-in-the-middle attacks.

A cookie that was sent from the server to the browser.
max-age= sets the maximum lifetime of the cookie in seconds.
domain= sets the domain to which the cookie will be sent.
path= indicates the path that must exist in the requested URL for the browser to send the cookie.
secure instructs the browser to only send the cookie back when HTTPS requests are used, making it more resistant to man-in-the-middle attacks.

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 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 comparing against Max-Age or Expires.

The Via header tracks how a page is forwarded from proxy to proxy. Beware, not all proxies append themselves to the Via header.

Fastly's shield and edge servers that were queried for the request.

The page was not served from a cache.

The number of times this page has been served from the Varnish cache. Higher numbers are better.

Provides timing information about the journey of a request through Fastly's network. Format: s<timestamp>,vs<seconds>,ve<seconds>, where s is the start time of the request, ve stands for Varnish start and ve stands for Varnish end. The length of the trip is ve - vs milliseconds.

The alt-svc header advertises alternative services for accessing the same resource, enabling protocol negotiation and potential performance improvements.
h3 indicates that HTTP/3 is supported. Variants like h3-29 refer to specific drafts of the HTTP/3 protocol.
ma=7200 specifies that the alternative service information is fresh for 7200 seconds.

The size of the message body, in bytes.

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.