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 comparing against Max-Age or Expires.

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

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 cf-ray header provides a unique identifier for each request through Cloudflare. It's useful for troubleshooting and tracking requests in Cloudflare logs.

Warning The dynamic status indicates that Cloudflare did not cache the requested HTML page, similar to a "cache miss". By default, Cloudflare caches static assets such as images, CSS, and JavaScript but excludes HTML due to its dynamic nature. To cache HTML content, change the 'Cache Level' setting from dynamic to cache everything in Cloudflare. This adjustment allows HTML pages to be cached, leveraging Cloudflare's global network for faster and more efficient content delivery.

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 time in seconds that the page has been in the shared proxy cache. The maximum age is set by max-age or s-maxage in the Cache-Control header.

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.
must-revalidate indicates that once a page becomes stale, both shared caches and browser caches must not use their stale copy without validating it with the origin server first.
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 pre-check is a legacy directive introduced by Internet Explorer 5 and is no longer supported. No other browser supports it. Including pre-check is unnecessary, wastes bandwidth and processing power.
Notice post-check is a legacy directive introduced by Internet Explorer 5 and is no longer supported. No other browser supports it. Including post-check is unnecessary, wastes bandwidth and processing power.

This Expires date is in the past: the page is considered stale and will be removed from all caches.
Notice Because there is a Cache-Control header with a max-age and/or s-maxage directive, the Expires header will be ignored. Consider removing Expires to save bandwidth and processing power.

A cookie that was sent from the server to the browser.
expires= sets the maximum lifetime of the cookie using a specific date.
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.
Warning samesite=none instructs the browser to send the cookie to all cross-site requests, such as on requests to load images or frames from other sites. This enables third-party sites to log cookie data. This could lead to data leaks and cross-site request forgery attacks. To improve security, set to samesite=strict or samesite=lax.
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.
expires= sets the maximum lifetime of the cookie using a specific date.
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.
httponly forbids JavaScript from accessing the cookie. Helps mitigate the risk of client side scripts accessing a protected cookie.
cf_bm is a cookie set by Cloudflare to support bot management. This is a technical cookie; it's exempt from GDPR and doesn't need user consent.

A cookie that was sent from the server to the browser.
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.
Warning samesite=none instructs the browser to send the cookie to all cross-site requests, such as on requests to load images or frames from other sites. This enables third-party sites to log cookie data. This could lead to data leaks and cross-site request forgery attacks. To improve security, set to samesite=strict or samesite=lax.
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.
httponly forbids JavaScript from accessing the cookie. Helps mitigate the risk of client side scripts accessing a protected cookie.

The Vary header specifies a list of headers that must be considered when caching responses. For a cached response to be used, these headers must match between the cached response and the new request. This ensures that the appropriate version of a resource is served based on factors like language, encoding, or device type.
Notice This request has many Vary headers. More headers decrease the likelihood of a cache hit.

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

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.

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.

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

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.

A custom header used by Vimeo, likely for device detection or user segmentation purposes.

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