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Performance · 9 September 2026

Cache-Control Headers: Caching Guidance for HTML

Cache-Control tells clients and intermediaries how a response may be stored. Missing policy is a configuration review, not proof that a page is slow or that one universal cache setting is safe.

Quick answer

Set an intentional Cache-Control policy for HTML responses based on how frequently the content changes and whether it is public or personalised. A missing header deserves review, but the correct directive depends on the response—not on a blanket recommendation to cache everything.

What the issue means

Cache-Control controls caching behaviour for browsers and shared caches. Directives such as public, private, no-store, max-age, and no-cache have different consequences.

Why it matters for SEO

Caching affects delivery efficiency and freshness more directly than rankings. Public pages that can be reused may benefit from caching; account pages and sensitive responses need stricter controls.

How NOTABIS detects it

The cache-policy-review rule checks whether the measured HTML response advertises a Cache-Control policy. It does not benchmark cache hit rates, CDN behaviour, or freshness correctness.

How to check it yourself

Inspect the final response headers with browser developer tools or curl -I. Check cache headers at the origin and CDN, and test both anonymous and authenticated responses where relevant.

How to fix it

Choose directives per response class. Cache public versioned or stable content for an appropriate period; use private or no-store handling for personalised or sensitive responses. Purge or revalidate content deliberately after important changes.

When it may be intentional

A dynamic, personalised, authenticated, or security-sensitive response may intentionally avoid shared caching. Document that policy rather than adding a header that could leak content.

Related issues

Review response time, compression, large HTML, and security headers separately.

Run a NOTABIS audit

An audit shows the final response headers observed for affected pages so you can distinguish missing policy from an intentionally uncached response.

Measure before you change

See which issues affect your site.
Run a NOTABIS audit ↗