HTTP X-fstrz headers provide information on what the engine did or did not do:

  • p: proxy request / response
  • w, p: optimization in progress
  • Z, p: non-optimizable page (will never be optimized, 404, 301, 302, POST, etc ...). The reason is given by another flag:
    • m : method (HEAD, PROPFIND, OPTIONS, PUT, DELETE, etc)
    • ecc: exclusion via the client config
    • eec: exclusion via the engine config
    • stc: status code of the origin different from 200
    • ab: exclusion by A / B test
    • zc: empty content
  • When no additional flags are present, the optimizations are simply disabled.
  • h: content that is not HTML (JSON sent with a content type text / html for example)
  • o: optimized
  • !o: not optimized
  • c: hidden
  • !c: not hidden
  • o,c: optimized, hidden
  • w,c: response being optimized but served hidden
  • dc,o: optimized, dynamic cache (internal engine operation)
  • sc: the page is hidden via SmartCache (Cache + Ajax)
  • clc: the page is hidden via the Cookie Less Cache
  • ed: engine disabled
  • v: virtual object (result of concatenation or outlining)
  • vf: reconstituted virtual object
  • t: timeout, the optimization took too long, the returned page is not optimized
  • e: error, optimization failed, the returned page is not optimized
  • b: blocked, the IP address is blocked
  • uc: User Canceled, the request was canceled by the user
  • cbo: Circuit Breaker Open, the object is not optimized due to the temporary unavailability of an engine component
  • ccb: Cache CallBack, the object is served by the proxy from the cache (case of an object that has not yet been included in an A / B test)
  • of: Overflow, indicates that the overflow system is in place. The following flags specify the result.
    • !id: no ID present
    • exp: the session has expired
    • !conf: no configuration found
    • !en: not activated
    • wen: has been activated
    • in: activated
    • say: disallow, the user was returned to the waiting page
    • r : HTTP redirection made by Fasterize

The header x-unique-id corresponds to the unique identifier of the request (to be transmitted to the support in case of problem).