HTTP Cache Simulator & CDN Policy Generator

RFC 9111 decision simulator

Simulate HTTP cache freshness, audit headers and generate reviewable CDN policies.

—Decision

0sCurrent age

0sFreshness lifetime

0Errors

1Warnings

Request headers

Response headers

How to use it

01
Paste request and response headers
Set method, status, cache context, elapsed time and optional network failure.
02
Explain the cache decision
Calculate corrected current age, freshness lifetime, stale windows, validators and storage constraints.
03
Build deployment policy
Review risky combinations and export path-specific headers for Cloudflare Pages or another web server.

Does this contact a CDN?

No. It models supplied HTTP evidence locally and never claims to observe a live edge cache.

What is the difference between no-cache and no-store?

No-cache permits storage but requires validation before reuse; no-store instructs caches not to store the response.

Which specification is modeled?

The simulator follows practical RFC 9111 storage, age and freshness rules, with explicit explanations and bounded inputs.

Do generated headers guarantee provider behavior?

No. CDN cache keys, product settings, Workers or Functions and provider-specific overrides must also be verified.

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