DNS
Resolvers can return different cached records depending on geography, TTL and propagation state.
Network & Web Tools
Pro diagnostic reportCache-Control Header Analyzer Online Free
Analyze response caching directives and understand how browsers, proxies and CDNs may store and reuse content.
Diagnose
Run a bounded public check.
Understand
See a health score and explanation.
Act
Follow prioritized recommendations.
Analyze caching policy
Paste response caching headers to understand browser and shared-cache behaviour.
Grade
A
Score
100/100
Directives
4
public
Enabled
max-age
3600
s-maxage
86400
stale-while-revalidate
60
Warnings
- No major conflicts detected.
Suggestions
- Policy is explicit and internally consistent.
About this tool
HTTP caching improves performance and reduces server load, but conflicting or unclear directives can cause stale content or unnecessary requests. This browser-only analyzer explains the policy and flags common problems.
Common use cases
- ✓ Review static asset caching before deployment.
- ✓ Compare browser and CDN cache lifetimes.
- ✓ Find conflicting public, private or no-store directives.
- ✓ Check whether immutable or revalidation directives fit a policy.
How to use it
- Paste the Cache-Control header value.
- Optionally add an Expires header.
- Review directives, score and warnings.
- Adjust your server or CDN configuration and test again.
Important interpretation notes
- • The score is guidance, not a universal rule for every response type.
- • Sensitive responses often need stricter caching than public assets.
- • CDNs can apply configuration that differs from the origin header.
Professional interpretation guide
Understand and verify your cache-control header analyzer results
Use the result as a focused diagnostic signal. Verify important findings before changing DNS, hosting, security, caching or application configuration.
What the result tells you
- ✓ Directives describe whether and for how long browsers or shared caches may reuse a response.
- ✓ Freshness values such as max-age and s-maxage target different cache layers.
- ✓ Revalidation directives influence what happens after freshness expires.
How to verify it
- Compare with the live response headers.
- Test CDN and browser behaviour independently.
- Confirm that personalized or sensitive responses are not publicly cached.
Network diagnostics
Interpret results in the correct protocol layer
Network tools observe different layers: DNS resolves names, TCP establishes connections, TLS authenticates encrypted sessions and HTTP carries requests, redirects, headers and caching rules. A successful result at one layer does not prove that the complete website or application is healthy.
TLS
Certificate validity, hostname matching, trust chains and protocol support are separate checks.
HTTP
Status codes, redirect chains, headers and caching directives describe application behaviour.
Measurement context
Latency and reachability vary by location, network path, browser and time.
What the operation can change
- A cached DNS answer may differ from an authoritative nameserver response.
- A 200 status code can still return the wrong content or an application error page.
- A valid certificate does not prove the website itself is trustworthy.
- Security-header tools report configuration, not complete vulnerability coverage.
Domain-specific verification
- Repeat tests from another network or resolver when location matters.
- Check the final URL and every redirect hop.
- Confirm timestamps, certificate names and expiry dates.
- Use browser developer tools and server logs for production incidents.
Common mistakes to avoid
- • Applying one policy to every asset and document.
- • Confusing no-cache with no-store.
- • Using long cache lifetimes without versioned asset URLs.
Privacy and safe use
Header text is analyzed locally. When copied from production, review it for internal identifiers before sharing.
Limitations
- • Actual caching also depends on validators, CDN rules and intermediary behaviour.
- • The analyzer cannot observe every cache between a user and the origin.
Continue the diagnostic workflow
Combine related checks instead of relying on one isolated result.
Related Network & Web Tools
Frequently asked questions
What does max-age control?
max-age defines how many seconds a response may remain fresh in a browser cache before revalidation is needed.
What is s-maxage?
s-maxage defines freshness for shared caches such as CDNs and generally overrides max-age for those caches.
Is no-cache the same as no-store?
No. no-cache permits storage but requires validation before reuse, while no-store tells caches not to store the response.
Should every response be cached?
No. Personal, sensitive and rapidly changing responses may require private, no-cache or no-store policies.