TL;DR

  • Cache-Control shows max age.
  • Age shows current cached age.
  • X-Cache or CF-Cache-Status indicates hit/miss.

Detection Signals

  • Cache-Control: max-age=...
  • Age: ...
  • X-Cache: HIT|MISS
  • CDN headers like CF-Cache-Status, X-Served-By

Notes

  • Combine headers with response timing to confirm caching.
  • Vary query params to confirm cache keys.