HTTP Cache Planner

Build Cache-Control policies or explain pasted header values with TTL math, companion header guidance, and practical caching notes.

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Quick samples

Choose your workflow

Start from a practical recipe and tune browser/CDN behavior before implementation.

Plan the policy

Tune browser and shared-cache behavior with a recipe-first form.

Long-lived immutable files such as hashed JS or CSS bundles.

`max-age` in seconds for browser caches.

`s-maxage` in seconds for CDNs and other shared caches.

Optional background-refresh window in seconds.

Optional origin-failure fallback window in seconds.

Turn this on only when the URL changes whenever the file contents change.

Your cache policy

Build a policy or explain an existing header to get a copy-ready result.

No cache policy yet

Start with a recipe or paste a Cache-Control value to see the final header, how it behaves, and what else you need to implement it well.