HTTP Response Headers

Upon responding to the requesting client, iSmartFrame appends extra HTTP headers elucidating the transaction outcome and events transpiring on iSF's end. These headers prove invaluable for comprehending the process when soliciting a web resource on your site and are viewable via your browser's developer console, within the network tab.


The cache status can be one of the following:

  • HIT: the resource is cached and served by iSmartFrame's caching system.

  • EXTRACTING: the resource is not in cache but is being inserted into it. The next request for this particular resource will result in a HIT.

  • MISS: the resource is not in the cache, and it cannot be inserted into it.

  • DYNAMIC: the cache for this resource can't be delivered to the current client due to various potential factors (e.g., user login status).


This header provides information about the current cache status for the resource. It specifically includes the caching date and the cache age in the following format:

YYYY-MM-DDTHH:MM:SS.Z (GMT) (<<elapsed time>> of <<max cache time>>)

This header appears only then the cache status is HIT.


The iSmartFrame transaction status will always be printed in this header, along with some helpful debug information primarily utilized by the Debug Tool to display useful details.


Same as the X-Isf-Shield-Req-Id headers sent to the backend. This header displays the current transaction identifier.


This header is visible exclusively when the current resource is bypassed by iSmartFrame. It may indicate one of the following statuses:

  • SOFT_* or HARD_*: iSF fully bypasses the resource, ensuring that iSmartFrame does not process or cache it. Instead, the transaction is entirely handled by the origin website's backend.

  • SKIP_MANIPULATION: the resource isn't processed by iSF, but it will be cached within our systems.

Please be aware that when the resource is in cache-bypass mode, this header will not be visible; however, the Isf-Kc-Status will be in DYNAMIC mode.

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