Version stable assets
Long freshness and immutable behavior are most practical for assets whose URL changes with their content. HTML and personalized responses often need different policies.
HTTP response headers · cache and crawler evidence
Inspect cache policy, validators, robots directives, and delivery headers
Follow a public URL to its terminal response and review exact cache directives, freshness windows, validators, representation metadata, X-Robots-Tag, HTTP Link relationships, and common browser security declarations—without turning their presence into an artificial score.
METHODHEADREDIRECTS5 MAXBODYNOT DOWNLOADED
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Ready for a public page or asset URL.
No example headers, cache grade, security score, or generated result is shown before the live HEAD request.
Interpret in deployment context
Use exact policy evidence instead of a one-size-fits-all grade
Retain validators
ETag and Last-Modified can support conditional requests when a response must be revalidated. Their presence does not establish that a cache reused the response.
Check crawler headers
X-Robots-Tag can carry indexing and serving directives for HTML and non-HTML resources. Crawlers must be able to fetch the URL to discover them.