Technical SEO
Cache headers
Cache headers are HTTP response fields that tell browsers and intermediaries whether, where and how long a representation may be reused.
What it means
`Cache-Control` directives define reuse and freshness, while validators such as `ETag` and `Last-Modified` support conditional requests after content becomes stale. Shared and private caches require different policies, especially when responses contain personalized or authenticated data.
Why it matters
Effective caching reduces repeat transfers and origin work, but an overbroad rule can expose private content or keep obsolete files in circulation. Versioned static assets can use long freshness, while changing HTML often needs revalidation or a shorter policy.
Example
A hashed CSS file receives a one-year immutable policy because a content change creates a new URL. An account page uses private revalidation instead of public caching, preventing one user's response from being reused for another.
Common mistakes
Do not assign long freshness to unversioned files, mark personalized pages public or assume `no-cache` means never store. Avoid contradictory directives and verify CDN behavior rather than reading only the origin response.
How AYSA handles this
Signals reviewed
Cache-Control, Age, ETag, Last-Modified, asset fingerprinting, response privacy
Problem AYSA can identify
AYSA can identify static files without effective reuse, stale unversioned assets and responses with unsafe shared-cache directives.
Recommendation prepared
The proposal assigns a policy by response class and documents invalidation, validation and personalization requirements.
Approval preview
The user reviews representative headers, cache path and stale-content or privacy risks before approval.
Execution
AYSA can apply approved WordPress and accessible server rules; CDN or reverse-proxy configuration may require its administrator.
Verification
AYSA performs cold, warm and conditional requests through the public path and confirms expected status, age and content.
Limits
Intermediaries can override origin rules, and AYSA cannot guarantee cache behavior in infrastructure it cannot inspect.
Sources and further reading
- MDN — HTTP caching — Web platform reference
- MDN — Cache-Control — Web platform reference
Written by Marius Dosinescu. Reviewed by AYSA SEO Editorial Team · 2026-07-28 00:00:00.
Quick answers
Frequently asked questions
Does Cache-Control: no-cache prevent storage?
No. It allows storage but requires validation before reuse; `no-store` is the directive that instructs caches not to store the response.
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