FAQ: CDN, cache, and performance

Does enabling the proxy cache the entire website?

No. Default behavior primarily identifies static assets by file extension; HTML and JSON are usually not cached automatically. Method, response headers, cookies, and rules continue to affect eligibility. Start with default cache behavior, not the assumption that Proxied means everything is cached.

Can HTML be cached?

Yes, but enable it only for an allowlist of public pages whose response is identical for every visitor. Bypass sign-in, account, cart, preview, and personalized routes first, or one user's response could be served to another.

What do DYNAMIC, BYPASS, MISS, and HIT mean?

DYNAMIC means the request was not cache eligible; BYPASS means it was eligible but the origin response or configuration prevented storage; MISS means cacheable but absent at request time; HIT is served from Cloudflare cache. Use why CF-Cache-Status is not HIT for evidence-based diagnosis.

Is a first MISS followed by a HIT normal?

Yes. A data center may fetch and fill the object on its first request, allowing a later request with the same cache key to hit. Purge, expiry, and eviction also restart this sequence. Test the same URL, client, and headers without changing other variables.

curl -sS -D - -o /dev/null https://example.com/assets/app.css
curl -sS -D - -o /dev/null https://example.com/assets/app.css

Why is a response with Set-Cookie not cached?

A cookie often signals a session or personalization, so default and rule behavior treat such responses cautiously. Confirm whether the cookie is necessary and the response is truly public before making a narrow origin or rule change. Do not delete every cookie or force private content into cache to obtain a HIT.

Does Purge Everything fix cache problems?

It removes objects but does not repair eligibility, cache-key, or response-header mistakes, and it forces broad origin refill. Prefer content-hashed asset URLs and targeted URL, tag, or prefix purges. See the purge and release workflow.

Why does a browser show old content after Cloudflare was purged?

Edge and browser caches are separate. A Cloudflare purge cannot delete an object already stored on a visitor's device. Inspect Cache-Control, Browser TTL, service workers, and whether HTML still references an old asset. Compare a private window with curl rather than relying on one reload.

Is a cache key safer when it has more dimensions?

No. Too few dimensions can create cross-reads or poisoning; too many fragment cache and lower hit rate. Include only query parameters, headers, cookies, or device dimensions that actually change the response. Use the cache-key security guide.

Primary sources

• Default cache behavior
• Cache responses
• Investigate uncached responses
• Cache Rules
• Purge cache