no-cache cache directive
no-cache requires validation before reuse; it does not mean do not store.
- caching
- directives
- validation
Response meaning
An unqualified no-cache response directive allows storage but prohibits reuse
without successful validation with the origin.
Cache-Control: no-cache
ETag: "manual-v4"
Expected result: a cache can store the response, then use the entity tag to validate before each reuse. A matching condition can produce 304.
Request meaning
In a request, no-cache tells caches not to use a stored response without successful validation. It does not guarantee a complete end-to-end reload if another application layer supplies content.
Common mistake
Use no-store when the intent is to prohibit cache storage. Neither directive
erases copies outside compliant HTTP caches or replaces encryption and access
control.