HTTP caching: no-cache requires validation, while no-store restricts storage
Use response no-cache when reuse requires origin validation; use no-store when an ordinary compliant cache must not retain the response.
- Applies when
- HTTP response caching under RFC 9111
- Tested environment
- Standards-based explanation reviewed 2026-11-07; no CDN or browser test
The names are easy to misread. An unqualified response Cache-Control: no-cache does not simply mean “never save this response.” A cache can retain it, but must validate successfully with the origin before using it for another request. This can enable conditional requests rather than downloading the representation again.
Response no-store normally prohibits storing the immediate request or response and using that response for another request. It is a cache instruction, not an encryption, access-control, or guaranteed data-erasure mechanism.
Illustrative choice: a frequently changing public page might allow storage but require validation; a sensitive response might require a storage restriction. Decide separately whether shared caches are allowed: private concerns shared-cache storage and is another distinct control.
Check the complete response headers and actual browser or intermediary behavior. Avoid asserting that an application is confidential merely because one cache directive is present. Extensions and cache-specific configuration can matter.
Evidence: RFC semantics reviewed, not a browser/CDN conformance test. This post describes unqualified response directives, not every request or field-qualified variant.
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