Cloudflare: cf-cache-status: DYNAMIC

Quick fix

Read the commands before running them. Anything that restarts a service, deletes data or changes permissions should be tried on a non-production system first.

# What does Cloudflare say, and what did the origin send?
curl -sI https://example.com/ | grep -iE 'cf-cache-status|cache-control|set-cookie|age'

# DYNAMIC: not eligible (needs a Cache Rule)
# MISS / EXPIRED: eligible, just not stored yet
# BYPASS: origin said no-cache, private or sent Set-Cookie

# Fix: Caching > Cache Rules > Create rule
#   When: hostname eq example.com and path starts with /blog/
#   Then: Eligible for cache, Edge TTL: respect origin

# Origin side, for pages that are safe to share
# Cache-Control: public, max-age=300

# Request twice and confirm the second is a HIT
curl -sI https://example.com/blog/ | grep -i cf-cache-status

How to diagnose Caching errors

Cache problems are rarely reported as cache problems. They arrive as a traffic spike that takes down the origin (a stampede after a mass eviction), users seeing old content after a deploy, or an inexplicable 403 from the CDN. The unifying diagnostic is to look at the cache status header on a real response before theorising about anything else.

If the quick fix above does not resolve it, work through these steps. They apply to this whole class of error, not just to this one message, which is usually what saves the time.

1. Read the cache status header on a live request: curl -sI https://example.com | grep -i -E 'cache|age|x-cache|cf-cache-status'. HIT, MISS and BYPASS each point at a different root cause.
2. Check the Age header against your intended TTL. An Age larger than max-age means something is serving stale content deliberately (stale-while-revalidate), often the desired behaviour, occasionally the bug.
3. For stampedes, add request coalescing or a short randomised TTL jitter rather than a longer TTL. Identical expiry times across many keys are what create the thundering herd.
4. Use content-hashed filenames for static assets and no-cache for HTML. Almost every "users see the old version" incident traces back to a long TTL on an HTML document.
5. For CDN 403s, distinguish a CDN-generated response from an origin one by checking whether CDN-specific headers are present. An origin 403 has a completely different fix.

Tools worth reaching for

• curl -sI
• varnishlog
• CDN edge logs
• Cache-Control validators

Authoritative references

Primary documentation for this error, worth reading before applying any fix in production.

📖 developers.cloudflare.com 📖 developers.cloudflare.com

Related Caching errors

• Browser serving stale cache after deploymentUsers see old content after a deployment because their browsers cached the previous version…
• Cache stampede / thundering herdMultiple processes simultaneously attempt to rebuild the same expired cache entry…
• CDN: High cache miss ratioThe CDN is not caching responses effectively. Most requests are hitting the origin server…
• CloudFront: 403 Access DeniedCloudFront cannot access the S3 origin, usually because the bucket policy or Origin Access…
• CloudFront: 502 ERROR The request could not be satisfied (origin SSL failure)CloudFront connected to the origin over HTTPS but the TLS negotiation failed, so it returned…
• CloudFront: 504 ERROR The request could not be satisfied (origin timeout)CloudFront reached for your origin and either could not open a connection or got no response…
• Django: CacheKeyWarning: Cache key will cause errors if used with memcachedMemcached keys must be under 250 bytes and contain no spaces or control characters. Django…
• Memcached: SERVER_ERROR object too large for cacheThe item exceeded the maximum item size, one megabyte by default, so it was refused rather…

See all 20 Caching errors →

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Something missing or wrong?

This entry is maintained by hand. If the fix is out of date, incomplete, or you have a better one, email a correction and it will be reviewed.